The old variables still work. The global lets us avoid
auto-detection logic like we're currently doing for
`matrix_nginx_proxy_proxy_matrix_federation_api_enabled`.

In the future, we'd just be able to reference
`matrix_homeserver_federation_enabled` and know the up-to-date value
regardless of homeserver.

This was meant to serve as an intermediary for services needing to reach
the homeserver. It was used like that for a while in this
`bye-bye-nginx-proxy` branch, but was never actually public.

It has recently been superseded by homeserver-like services injecting
themselves into a new internal Traefik entrypoint
(see `matrix_playbook_internal_matrix_client_api_traefik_entrypoint_*`),
so `matrix-homeserver-proxy` is no longer necessary.

---

This is probably a good moment to share some benchmarks and reasons
for going with the internal Traefik entrypoint as opposed to this nginx
service.

1. (1400 rps) Directly to Synapse (`ab -n 1000 -c 100 http://matrix-synapse:8008/_matrix/client/versions`
2. (~900 rps) Via `matrix-homeserver-proxy` (nginx) proxying to Synapse (`ab -n 1000 -c 100 http://matrix-homeserver-proxy:8008/_matrix/client/versions`)
3. (~1200 rps) Via the new internal entrypoint of Traefik (`matrix-internal-matrix-client-api`) proxying to Synapse (`ab -n 1000 -c 100 http://matrix-traefik:8008/_matrix/client/versions`)

Besides Traefik being quicker for some reason, there are also other
benefits to not having this `matrix-homeserver-proxy` component:

- we can reuse what we have in terms of labels. Services can register a few extra labels on the new Traefik entrypoint
- we don't need services (like `matrix-media-repo`) to inject custom nginx configs into `matrix-homeserver-proxy`. They just need to register labels, like they do already.
- Traefik seems faster than nginx on this benchmark for some reason, which is a nice bonus
- no need to run one extra container (`matrix-homeserver-proxy`) and execute one extra Ansible role
- no need to maintain a setup where some people run the `matrix-homeserver-proxy` component (because they have route-stealing services like `matrix-media-repo` enabled) and others run an optimized setup without this component and everything needs to be rewired to talk to the homeserver directly. Now, everyone can go through Traefik and we can all run an identical setup

Downsides of the new Traefik entrypoint setup are that:

- all addon services that need to talk to the homeserver now depend on Traefik
- people running their own Traefik setup will be inconvenienced - they
  need to manage one additional entrypoint

We'd be adding integration with an internal Traefik entrypoint
(`matrix_playbook_internal_matrix_client_api_traefik_entrypoint`),
so renaming helps disambiguate things.

There's no need for deperecation tasks, because the old names
have only been part of this `bye-bye-nginx-proxy` branch and not used by
anyone publicly.

This also adds labels for Synapse. Support for other homeservers and
components will be added later.

`matrix_homeserver_container_url` is potentially wrong in certain
scenarios (going through `matrix-homeserver-proxy`).

Related to https://github.com/spantaleev/matrix-docker-ansible-deploy/pull/3086

ldap-registration-proxy is already connected to the homeserver
container's network by default (via group vars), so there's no need for this.

This reverts commit bf95ad2235.

This was a bad idea.
It's better to have people manually define the password.

Otherwise, `matrix_homeserver_generic_secret_key` changing some day in
the future would break the bot and one would have to figure out how to
reset its password manually.

Using an explicit password is more stable.

Running just `setup-all,start` is not enough, because it doesn't run `ensure-matrix-users-created`
and the bot account won't get created.

This is split out from matrix-cactus-comments (see 241779b583),
but also heavily inspired by `matrix-static-files`.

This also updates validation tasks and documentation, pointing to
variables in the matrix-synapse role which don't currently exist yet
(e.g. `matrix_synapse_container_labels_client_synapse_admin_api_enabled`).

These variables will be added soon, as Traefik labels are added to the
`matrix-synapse` role. At that point, the `matrix-synapse-reverse-proxy-companion` role
will be updated to also use them.

matrix-nginx-proxy is going away and this is one of the features it
offered.

This feature will have no equivalent in our new Traefik-only
setup, although it's possible to implement it manually by using
`matrix_client_element_container_labels_additional_labels`

The spec had gotten updated

In nginx reverse-proxy, when the upstream server relies on SNI, the reverser-proxy may return 502 by follow error:
```
*10 SSL_do_handshake() failed (SSL: error:0A000410:SSL routines::sslv3 alert handshake failure:SSL alert number 40) while SSL handshaking to upstream, client: 172.19.0.1, server: example.host, request: "GET /.well-known/matrix/client HTTP/2.0", upstream: "https://<ip>/.well-known/matrix/client", host: "<domain>"
```
This problem often arises when the upstream server is behind the CDN, setting `proxy_ssl_server_name` to `on` will solve it.

* Updated MMR docs with updated fields in main.yaml

* Removed uneeded placeholder db password

* Update prerequisites.md

Document that sudo is required.

* Relocate sudo requirement in prerequisites and reword

---------

Co-authored-by: Slavi Pantaleev <slavi@devture.com>

Squashed based on the work done in https://github.com/spantaleev/matrix-docker-ansible-deploy/pull/3042

commit 49932b8f3c
Author: Slavi Pantaleev <slavi@devture.com>
Date:   Sat Dec 16 09:21:31 2023 +0200

    Fix syntax in matrix-bridge-hookshot/tasks/reset_encryption.yml

    Also, this task always does work and side-effects, so it should always report changes
    (`changed_when: true`).

commit 6bdf7a9dcb
Author: Slavi Pantaleev <slavi@devture.com>
Date:   Sat Dec 16 09:12:41 2023 +0200

    Add Hookshot validation task to ensure queue settings are set when encryption is enabled

commit 8c531b7971
Author: Slavi Pantaleev <slavi@devture.com>
Date:   Sat Dec 16 09:10:17 2023 +0200

    Add missing variables rewiring in group_vars/matrix_servers for Hookshot

commit 7d26dabc2f
Author: Slavi Pantaleev <slavi@devture.com>
Date:   Sat Dec 16 09:08:19 2023 +0200

    Add defaults for matrix_hookshot_queue_host and matrix_hookshot_queue_port

commit 74f91138c9
Author: Slavi Pantaleev <slavi@devture.com>
Date:   Sat Dec 16 09:06:17 2023 +0200

    Fix syntax for connecting to additional networks for Hookshot

commit ca7b41f3f2
Author: Slavi Pantaleev <slavi@devture.com>
Date:   Sat Dec 16 09:05:28 2023 +0200

    Fix indentation and remove unnecessary if-statements

commit ac4a918d58
Author: Slavi Pantaleev <slavi@devture.com>
Date:   Sat Dec 16 09:04:44 2023 +0200

    Add missing --network for Hookshot

    This seems to have been removed by accident.

commit 6a81fa208f
Author: Slavi Pantaleev <slavi@devture.com>
Date:   Sat Dec 16 09:02:47 2023 +0200

    Make automatic Redis enabling safer, when Hookshot encryption enabled

    If we ever default encryption to enabled for Hookshot, we only wish to force-enable Redis if Hookshot is actually enabled.

commit 75a8e0f2a6
Author: Slavi Pantaleev <slavi@devture.com>
Date:   Sat Dec 16 09:01:10 2023 +0200

    Fix typo

commit 98ad182eac
Author: Joshua Hoffmann <joshua.hoffmann@b1-systems.de>
Date:   Fri Dec 15 22:37:40 2023 +0100

    Add defaults for Hookshot's encryption

commit 29fa9fab15
Author: Joshua Hoffmann <joshua.hoffmann@b1-systems.de>
Date:   Fri Dec 15 22:35:11 2023 +0100

    Improve wording of Hookshot's encryption section

commit 4f835e0560
Author: Joshua Hoffmann <joshua.hoffmann@b1-systems.de>
Date:   Fri Dec 15 22:28:52 2023 +0100

    use safer mount options for the container's files

commit 8c93327e25
Author: Joshua Hoffmann <joshua.hoffmann@b1-systems.de>
Date:   Fri Dec 15 22:26:01 2023 +0100

    fix filename

commit 03a7bb6e77
Merge: e55d7694 06047763
Author: Joshua Hoffmann <joshua.hoffmann@b1-systems.de>
Date:   Fri Dec 15 22:23:44 2023 +0100

    Merge branch 'HarHarLinks/hookshot-encryption' of https://github.com/real-joshua/matrix-docker-ansible-deploy into HarHarLinks/hookshot-encryption

commit 06047763bb
Author: Joshua Hoffmann <joshua.hoffmann@b1-systems.de>
Date:   Fri Dec 15 22:15:54 2023 +0100

    Update roles/custom/matrix-bridge-hookshot/templates/config.yml.j2

    change the if statement to not require a variable with a length > 0 and add a filter to json for the redis host

    Co-authored-by: Slavi Pantaleev <slavi@devture.com>

commit e55d769465
Author: Joshua Hoffmann <joshua.hoffmann@b1-systems.de>
Date:   Fri Dec 15 22:13:50 2023 +0100

    clarify that Redis is required, standardadise on Hookshot with an upper-case first letter for consistency

commit 66706e4535
Author: Joshua Hoffmann <joshua.hoffmann@b1-systems.de>
Date:   Fri Dec 15 22:08:20 2023 +0100

    Update roles/custom/matrix-bridge-hookshot/templates/config.yml.j2

    fix for a typo

    Co-authored-by: Slavi Pantaleev <slavi@devture.com>

commit f6aaeb9a16
Merge: e5d34002 869dd33f
Author: Joshua Hoffmann <joshua.hoffmann@b1-systems.de>
Date:   Fri Dec 15 00:22:34 2023 +0100

    Merge branch 'master' into HarHarLinks/hookshot-encryption

commit e5d34002fd
Author: Joshua Hoffmann <joshua.hoffmann@b1-systems.de>
Date:   Fri Dec 15 00:09:27 2023 +0100

    Add Jinja loop to allow adding multiple networks

commit 69f947782d
Author: Joshua Hoffmann <joshua.hoffmann@b1-systems.de>
Date:   Thu Dec 14 23:52:41 2023 +0100

    split if statements for the message queue and experimental encryption support into seperate statements

commit 4c13be1c89
Author: Joshua Hoffmann <joshua.hoffmann@b1-systems.de>
Date:   Thu Dec 14 23:31:19 2023 +0100

    change variable name per spantaleev's suggestion (https://github.com/spantaleev/matrix-docker-ansible-deploy/pull/2979#discussion_r1379015551)

commit 9905309aa9
Author: HarHarLinks <kim.brose@rwth-aachen.de>
Date:   Wed Nov 1 16:14:04 2023 +0100

    amend docs

commit 94abf2d5bd
Author: HarHarLinks <kim.brose@rwth-aachen.de>
Date:   Wed Nov 1 16:05:22 2023 +0100

    draft encryption support for hookshot