* Add a global config option for Docker network MTU

* Upgrade systemd_docker_base (v1.2.0-0 -> v1.3.0-0)

The new version includes `devture_systemd_docker_base_container_networks_driver_options`
due to 3cc7d12396

Related to https://github.com/spantaleev/matrix-docker-ansible-deploy/pull/3502

* Switch from passing matrix_playbook_docker_network_mtu to respecting devture_systemd_docker_base_container_networks_driver_options

Related to:
- 3cc7d12396
- https://github.com/spantaleev/matrix-docker-ansible-deploy/pull/3502

* Update all roles to versions that respect `devture_systemd_docker_base_container_networks_driver_options`

---------

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

As reported in https://github.com/spantaleev/matrix-docker-ansible-deploy/issues/3451#issuecomment-2331316593

Likely the solution to https://github.com/spantaleev/matrix-docker-ansible-deploy/issues/3451

No need to duplicate the same logic as in `group_vars/matrix_servers`.

Having it disabled by default in the role itself and overriding it at the playbook level (based on the selected homeserver implementation) makes more sense.

This is provoked by de91fe933d94afcdbfdb0c6cf75a1dfa43dfdf43,
where I've added a few new labels and made it possible for people to
disable them.

In this patch, I'm making it possible to disable any of the old Traefik
labels in a similar way.

Related to:

- https://github.com/spantaleev/matrix-docker-ansible-deploy/pull/3409
- https://github.com/t2bot/matrix-media-repo/releases/tag/v1.3.5
- https://github.com/matrix-org/matrix-spec-proposals/pull/3916

Support for authenticated media routes is enabled by default, but
variables are in place to disable it if necessary.

This change has not been tested.

`matrix-media-repo` is the only role that seems incompatible with the
changes introduced by Traefik v3, due to its use of `PathPrefix` with
regular expressions in a few places.

Regular expressions should now be used with `PathRegexp`, not
`PathPrefix`. Furthermore, they should follow the Golang regexp syntax,
as described in the migration guide:
https://doc.traefik.io/traefik/migration/v2-to-v3-details/#dynamic-configuration-changes

Fixup for f97e849018

Fixes https://github.com/spantaleev/matrix-docker-ansible-deploy/issues/3354

Continuation of 9f2eff2ac7

Provoked by 7749048bf8
(https://github.com/spantaleev/matrix-docker-ansible-deploy/pull/3353)

Fixes https://github.com/spantaleev/matrix-docker-ansible-deploy/issues/3349

`docker.io/turt2live/matrix-media-repo:v1.3.4` is amd64-only.

`ghcr.io/t2bot/matrix-media-repo:v1.3.4` is a multi-arch image which
works on arm64.

commit cf8637efac
Author: Slavi Pantaleev <slavi@devture.com>
Date:   Sun Mar 24 19:14:57 2024 +0200

    Make devture_systemd_docker_base_ipv6_enabled automatically reconfigure geerlingguy/ansible-role-docker

    Related to https://github.com/spantaleev/matrix-docker-ansible-deploy/pull/3218

commit dc7af3bc7d
Author: Slavi Pantaleev <slavi@devture.com>
Date:   Sun Mar 24 19:10:31 2024 +0200

    Replace matrix_ipv6_enabled with devture_systemd_docker_base_ipv6_enabled

    Related to https://github.com/spantaleev/matrix-docker-ansible-deploy/pull/3218

commit 07e900d6a2
Author: Slavi Pantaleev <slavi@devture.com>
Date:   Sun Mar 24 19:01:51 2024 +0200

    Improve matrix_ipv6_enabled comments

commit 3f03ca7f69
Author: Tilo Spannagel <development@tilosp.de>
Date:   Sat Mar 9 19:27:50 2024 +0000

    Add setting to enable ipv6

This moves the comments from being just in Jinja,
to actually ending up in the generated `labels` file,
which makes inspection of the final result easier.

Also, some new lines were added here and there to make labels
more legible.

The generated file may still include weird new-lines due to
various `if` statements yielding content or not, but that's not so ugly
anymore - now that we have proper start/end sections that are visible in
the final `labels` file.

This is mostly so as to avoid referring to variables from other roles,
like `matrix_nginx_proxy_proxy_matrix_client_api_addr_with_container`.

This should come (and already does) from group_vars/matrix_servers

`matrix_media_repo_identifier` is already defined in the role defaults,
which is a better role to have it anyway.

* Updated MMR docs with updated fields in main.yaml

* Removed uneeded placeholder db password

This is backward-compatible with what we had before. We're not changing
the SSL mode - just making it configurable.

Most components are defaulting to `sslmode=disable`, while some
(`matrix-bot-matrix-reminder-bot` and others) do not specify an `sslmode` at all.

We're making sslmode configurable, because certain external Postgres
servers may be configured to require SSL encryption.
In such cases `sslmode=disable` does not work and needs to be changed to
`sslmode=require` or something else (`verify-ca`, `verify-full`, etc).