* feat: support container_network=host across all roles + systemd templates

Mirror the pattern Slavi introduced for matrix-coturn (aafa8f0) across the
fork: every 'Ensure X container network is created' task gets a
'when: <var> not in ["", "host"]' guard so MDAD does not try to
docker_network create a network literally named 'host' (returns 403,
since host is a pre-defined Docker network).

Mirror the same guard in every systemd unit template that does
'ExecStartPre=docker network connect <addnet> <container>' loops over
matrix_<role>_container_additional_networks: skip the connects when the
container is on host networking (where additional --network attaches
are invalid).

Unblocks DiD setups where MDAD-managed containers share their host's
network namespace (matrix-mdad outer compose service joined to central
postgres/openldap networks) to reach external services on the outer
Docker daemon.

* Simplify container network guards (!= 'host') and fix duplicate when

Guarding on the empty string ('') as well was misleading: systemd unit
templates still render an unconditional --network= flag, so an empty
network value produces a broken docker create command. Only 'host' is
actually supported, so only guard on that. This also matches the
existing convention in the Traefik role
(when: traefik_container_network != 'host').

Also fix a duplicate when key in the meshtastic-relay role, where the
network-creation task already had a when condition - the two are now
combined into a list.

Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>

---------

Co-authored-by: Slavi Pantaleev <slavi@devture.com>
Co-authored-by: Claude Fable 5 <noreply@anthropic.com>

Roles affected: appservice-discord, appservice-irc, beeper-linkedin,
heisenbridge, hookshot, mautrix-bluesky, mautrix-discord,
mautrix-gmessages, mautrix-googlechat, mautrix-signal, mautrix-slack,
mautrix-twitter, mautrix-whatsapp, mautrix-wsproxy, mx-puppet-groupme,
mx-puppet-steam, postmoogle, sms, steam, cactus-comments, element,
fluffychat, schildichat, conduit, corporal, dendrite,
ldap-registration-proxy, media-repo, pantalaimon,
prometheus-nginxlog-exporter, registration, sygnal, synapse-admin,
user-verification-service.

For each role: renamed _docker_image* variables to _container_image*
(and _docker_src_files_path to _container_src_files_path where
applicable), added deprecation entries in validate_config.yml, and
updated group_vars/docs references.

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

Related to https://github.com/spantaleev/matrix-docker-ansible-deploy/issues/4445

Signed-off-by: Suguru Hirahara <acioustick@noreply.codeberg.org>

`-t` works on both old and new Docker versions, so it's best to use that.

Currently v3.0.0 tested with no issues.
So remove matrix_user_verification_service_docker_image from groups_vars.

/.npm must be writable or an error will be reported.

Related to #2375, #2975, and #2847

Related to: https://github.com/spantaleev/matrix-docker-ansible-deploy/pull/2375#issuecomment-1656064975

Related to: https://github.com/spantaleev/matrix-docker-ansible-deploy/pull/2375#issuecomment-1655758296

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

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.