Related to 6a31fba346d9da434, 6a31fba346.

Related to https://github.com/Awesome-Technologies/synapse-admin/issues/322

Fixes https://github.com/spantaleev/matrix-docker-ansible-deploy/issues/2444

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

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

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

Applying the assumption, that synapse is always managed by this playbook.

This gets us started on adding a Traefik role and hooking Traefik:

- directly to services which support Traefik - we only have a few of
  these right now, but the list will grow

- to matrix-nginx-proxy for most services that integrate with
  matrix-nginx-proxy right now

Traefik usage should be disabled by default for now and nothing should
change for people just yet.

Enabling these experiments requires additional configuration like this:

```yaml
devture_traefik_ssl_email_address: '.....'

matrix_playbook_traefik_role_enabled: true
matrix_playbook_traefik_labels_enabled: true

matrix_ssl_retrieval_method: none

matrix_nginx_proxy_https_enabled: false

matrix_nginx_proxy_container_http_host_bind_port: ''
matrix_nginx_proxy_container_federation_host_bind_port: ''

matrix_nginx_proxy_trust_forwarded_proto: true

matrix_nginx_proxy_x_forwarded_for: '$proxy_add_x_forwarded_for'

matrix_coturn_enabled: false
```

What currently works is:
reverse-proxying for all nginx-proxy based services **except** for the Matrix homeserver
(both Client-Server an Federation traffic for the homeserver don't work yet)

Switching from doing "post-start" loop hacks to running the container
in 3 steps: `create` + potentially connect to additional networks + `start`.
This way, the container would be connected to all its networks even at
the very beginning of its life.

Related to https://docs.docker.com/engine/deprecated/#separator--of---security-opt-flag-on-docker-run

Update Prometheus to v2.42.0 from v2.41.0

Docker images are released now so this change can now be pushed.

Fix python packages path in synapse container

Container image not published yet.

Reverts #2438

Update synapse 1.75.0 -> 1.76.0; default room version 9 -> 10

Update prometheus 2.41.0 -> 2.42.0

Update element 1.11.21 -> 1.11.22

Update jitsi stable-8218 -> stable-8252

Update element 1.11.20 -> 1.11.21

Update cinny 2.2.3 -> 2.2.4