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>

Related to 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