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-corporal/defaults/main.yml

@@ -81,8 +81,10 @@ matrix_corporal_systemd_required_services_list_default: "{{ [devture_systemd_doc
 matrix_corporal_systemd_required_services_list_auto: []
 matrix_corporal_systemd_required_services_list_custom: []
 
-matrix_corporal_docker_image: "{{ matrix_corporal_docker_image_name_prefix }}devture/matrix-corporal:{{ matrix_corporal_docker_image_tag }}"
-matrix_corporal_docker_image_name_prefix: "{{ 'localhost/' if matrix_corporal_container_image_self_build else 'docker.io/' }}"
+matrix_corporal_docker_image: "{{ matrix_corporal_docker_image_registry_prefix }}devture/matrix-corporal:{{ matrix_corporal_docker_image_tag }}"
+matrix_corporal_docker_image_registry_prefix: "{{ 'localhost/' if matrix_corporal_container_image_self_build else matrix_corporal_docker_image_registry_prefix_upstream }}"
+matrix_corporal_docker_image_registry_prefix_upstream: "{{ matrix_corporal_docker_image_registry_prefix_upstream_default }}"
+matrix_corporal_docker_image_registry_prefix_upstream_default: docker.io/
 matrix_corporal_docker_image_tag: "{{ matrix_corporal_version }}"  # for backward-compatibility
 matrix_corporal_docker_image_force_pull: "{{ matrix_corporal_docker_image.endswith(':latest') }}"
 

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

@@ -26,3 +26,4 @@
   with_items:
     - {'old': 'matrix_corporal_container_expose_ports', 'new': '<superseded by matrix_corporal_container_http_gateway_host_bind_port and matrix_corporal_container_http_api_host_bind_port>'}
     - {'old': 'matrix_corporal_reconciliation_user_id_local_part', 'new': 'matrix_corporal_corporal_user_id_local_part'}
+    - {'old': 'matrix_corporal_container_image_name_prefix', 'new': 'matrix_corporal_docker_image_registry_prefix'}