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-synapse-admin/defaults/main.yml

@@ -15,8 +15,10 @@ matrix_synapse_admin_container_image_self_build_repo: "https://github.com/etkecc
 
 # renovate: datasource=docker depName=ghcr.io/etkecc/synapse-admin
 matrix_synapse_admin_version: v0.10.3-etke37
-matrix_synapse_admin_docker_image: "{{ matrix_synapse_admin_docker_image_name_prefix }}etkecc/synapse-admin:{{ matrix_synapse_admin_version }}"
-matrix_synapse_admin_docker_image_name_prefix: "{{ 'localhost/' if matrix_synapse_admin_container_image_self_build else 'ghcr.io/' }}"
+matrix_synapse_admin_docker_image: "{{ matrix_synapse_admin_docker_image_registry_prefix }}etkecc/synapse-admin:{{ matrix_synapse_admin_version }}"
+matrix_synapse_admin_docker_image_registry_prefix: "{{ 'localhost/' if matrix_synapse_admin_container_image_self_build else matrix_synapse_admin_docker_image_registry_prefix_upstream }}"
+matrix_synapse_admin_docker_image_registry_prefix_upstream: "{{ matrix_synapse_admin_docker_image_registry_prefix_upstream_default }}"
+matrix_synapse_admin_docker_image_registry_prefix_upstream_default: "ghcr.io/"
 matrix_synapse_admin_docker_image_force_pull: "{{ matrix_synapse_admin_docker_image.endswith(':latest') }}"
 
 # The base container network

roles/custom/matrix-synapse-admin/tasks/validate_config.yml

@@ -1,6 +1,6 @@
 ---
 
-- name: (Deprecation) Catch and report renamed settings
+- name: (Deprecation) Catch and report renamed matrix-synapse-admin settings
   ansible.builtin.fail:
     msg: >-
       Your configuration contains a variable, which now has a different name.
@@ -12,6 +12,7 @@
     - {'old': 'matrix_synapse_admin_container_self_build_repo', 'new': 'matrix_synapse_admin_container_image_self_build_repo'}
     - {'old': 'matrix_synapse_admin_public_endpoint', 'new': 'matrix_synapse_admin_path_prefix'}
     - {'old': 'matrix_synapse_admin_nginx_proxy_integration_enabled', 'new': '<removed>'}
+    - {'old': 'matrix_synapse_admin_docker_image_name_prefix', 'new': 'matrix_synapse_admin_docker_image_registry_prefix'}
 
 - when: matrix_synapse_admin_container_labels_traefik_enabled | bool
   block: