Replaces `community.docker.docker_image` with the modern
`docker_image_pull` module. Drops the `ansible_version` compatibility
ladder and the now-redundant `_container_image_force_pull` variable
(the new pull module handles registry refresh natively via `pull: always`).

Related to https://github.com/spantaleev/matrix-docker-ansible-deploy/issues/5191.

Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>

Add matrix_continuwuity_version with container_image_tag inheriting from it.
Rename all _docker_image* variables to _container_image* with deprecation notices.

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

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

* continuwuity support

* continuwuity support

* use main instead of commit tag

* fix docker image link

* migration from conduwuit

* fix yaml lint

* backup directories and linter fixes

* linter fixes