Fixes https://github.com/spantaleev/matrix-docker-ansible-deploy/issues/4297

Supersedes https://github.com/spantaleev/matrix-docker-ansible-deploy/pull/4300

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

This:

- brings consistency - no more mixing `_name_prefix` and `_registry_prefix`
- adds extensibility - a future patch will allow reconfiguring all registry prefixes for all roles in the playbook

We still have `_docker_` vs `_container_` inconsistencies.
These may be worked on later.

- Fix punctuations
- Set the common expression for matrix_authentication_service_config_email_mode

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

This makes it possible to migrate from Synapse when OIDC had been used
and the Synapse user database contains OIDC-sourced users.

Fixes https://github.com/spantaleev/matrix-docker-ansible-deploy/issues/3108

Related to https://github.com/spantaleev/matrix-docker-ansible-deploy/pull/3562