Check for empty string instead of Null to verify if an openid_server_name is pinned.

This is an advanced feature with dubious usefulness.
Putting it in the default config just confuses people.

Related to https://github.com/spantaleev/matrix-docker-ansible-deploy/pull/2220

We keep the Makefile for now, but don't mention it to new
users anymore.

Related to https://github.com/spantaleev/matrix-docker-ansible-deploy/pull/2227

Related to https://github.com/spantaleev/matrix-docker-ansible-deploy/pull/2386

Co-Authored-By: Slavi Pantaleev <slavi@devture.com>

* Allow the mautrix whatsapp relaybot to be enable with a variable

This allows a user to enable the relaybot by setting a variable in
`vars.yml` in the same way that the mautrix signal relaybot is
configured.

* Correct default values for mautrix whatsapp relaybot variables

* Add documentation for using the relaybot with mautrix whatsapp

* Adjust variable names to better reflect what they do

* Set default variables properly and use to_json in template

This extends the collection with support for seamless authentication at the Jitsi server using Matrix OpenID.

1. New role for installing the [Matrix User Verification Service](https://github.com/matrix-org/matrix-user-verification-service)
2. Changes to Jitsi role: Installing Jitsi Prosody Mods and configuring Jitsi Auth
3. Changes to Jitsi and nginx-proxy roles: Serving .well-known/element/jitsi from jitsi.DOMAIN
4. We updated the Jitsi documentation on authentication and added documentation for the user verification service.

This is a rebuild on Alpinelinux 3.17.0 (previously 3.16.2).
The new container image tag was pushed for arm32 and arm64 architectures
as well (2.13.6-r0 was `amd64`-only due to CI trouble in the past).

Fixes https://github.com/spantaleev/matrix-docker-ansible-deploy/issues/2353

This warning was added because of:
https://github.com/spantaleev/matrix-docker-ansible-deploy/issues/2090

The problem has since been fixed by:
e9e84341a9

This current patch was provoked by:
https://github.com/spantaleev/matrix-docker-ansible-deploy/pull/2352

Related to https://github.com/spantaleev/matrix-docker-ansible-deploy/pull/2351

Fixes https://github.com/spantaleev/matrix-docker-ansible-deploy/issues/2330

* Changes to allow a user to set the max participants on a jitsi
conference

* changed var name from jitsi_max_participants to matrix_prosody_jitsi_max_participants

* add prometheus-nginxlog-exporter role

* Rename matrix_prometheus_nginxlog_exporter_container_url to matrix_prometheus_nginxlog_exporter_container_hostname

* avoid referencing variables from other roles, handover info using group_vars/matrix_servers

* fix: stop service when uninstalling

fix: typo

move available arch's into a var

fix: text

* fix: prometheus enabled condition

Co-authored-by: ikkemaniac <ikkemaniac@localhost>

Related to https://github.com/spantaleev/matrix-docker-ansible-deploy/pull/2319

I'm not sure, but this should be changed to devture_postgres_... !?
https://github.com/spantaleev/matrix-docker-ansible-deploy/blob/master/CHANGELOG.md#2022-11-28

```yaml
matrix_postgres_process_extra_arguments: [
  "-c 'max_connections=200'"
]
```

Reference: https://borgbackup.readthedocs.io/en/stable/usage/general.html#repository-urls

Otherwise, we'd get:

> /etc/borgmatic.d/config.yaml: Remote repository paths without ssh:// syntax are deprecated. Interpreting "user@hostname:matrix" as "ssh://user@hostname/./matrix"

This role is usable on its own and it's not tied to Matrix, so
extracting it out into an independent role that we install via
ansible-galaxy makes sense.

This also fixes the confusion from the other day, where
`matrix_postgres_*` had to be renamed to `devture_postgres_*`
(unless it was about `matrix_postgres_backup_*`).
We now can safely say that ALL `matrix_postgres_*` variables need to be
renamed.

Fixes https://github.com/spantaleev/matrix-docker-ansible-deploy/issues/2305

Related to https://github.com/spantaleev/matrix-docker-ansible-deploy/pull/2256

Use up-to-date example from synapse docs

Add link to keycloak website

Add link to synapse docs on OIDC

Tests were carried out like this:

- `virtualenv3 env`
- `./env/bin/pip install ansible==4.10.0 ansible-core==2.11.7`
- `./env/bin/ansible-playbook .....`

The lowest version of `ansible-core` available on PyPI right now is
2.11.0. That version has trouble with `ansible==4.0.0` though.
The errors we were hitting seemed to be resolved by others online by
using `ansible==4.10.0` instead, which has a minimum `ansible-core`
requirement of `2.11.7`, so that's what we went with.

Older versions of Ansible may work, but.. I'm having trouble
installing them and don't want to spend too much time on digging through
ancient versions and testing them out. People should just learn to run
up-to-date software.