Rework all roles to include component_(docker|container)_image_registry_prefix* variables

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.

roles/custom/matrix-coturn/defaults/main.yml

@@ -10,8 +10,10 @@ matrix_coturn_container_image_self_build_repo_dockerfile_path: "docker/coturn/al
 
 # renovate: datasource=docker depName=coturn/coturn
 matrix_coturn_version: 4.6.2-r11
-matrix_coturn_docker_image: "{{ matrix_coturn_docker_image_name_prefix }}coturn/coturn:{{ matrix_coturn_version }}-alpine"
-matrix_coturn_docker_image_name_prefix: "{{ 'localhost/' if matrix_coturn_container_image_self_build else 'docker.io/' }}"
+matrix_coturn_docker_image: "{{ matrix_coturn_docker_image_registry_prefix }}coturn/coturn:{{ matrix_coturn_version }}-alpine"
+matrix_coturn_docker_image_registry_prefix: "{{ 'localhost/' if matrix_coturn_container_image_self_build else matrix_coturn_docker_image_registry_prefix_upstream }}"
+matrix_coturn_docker_image_registry_prefix_upstream: "{{ matrix_coturn_docker_image_registry_prefix_upstream_default }}"
+matrix_coturn_docker_image_registry_prefix_upstream_default: docker.io/
 matrix_coturn_docker_image_force_pull: "{{ matrix_coturn_docker_image.endswith(':latest') }}"
 
 # The Docker network that coturn would be put into.

roles/custom/matrix-coturn/tasks/validate_config.yml

@@ -10,6 +10,7 @@
     - {'old': 'matrix_coturn_docker_network', 'new': 'matrix_coturn_container_network'}
     - {'old': 'matrix_coturn_container_stun_plain_host_bind_port', 'new': 'superseded by matrix_coturn_container_stun_plain_host_bind_port_tcp and matrix_coturn_container_stun_plain_host_bind_port_udp'}
     - {'old': 'matrix_coturn_container_stun_tls_host_bind_port', 'new': 'superseded by matrix_coturn_container_stun_tls_host_bind_port_tcp and matrix_coturn_container_stun_tls_host_bind_port_udp'}
+    - {'old': 'matrix_coturn_container_image_name_prefix', 'new': 'matrix_coturn_docker_image_registry_prefix'}
 
 - name: Fail if matrix_coturn_authentication_method is invalid
   ansible.builtin.fail: