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-alertmanager-receiver/defaults/main.yml

@@ -25,11 +25,12 @@ matrix_alertmanager_receiver_container_image_self_build_repo: https://github.com
 matrix_alertmanager_receiver_container_image_self_build_repo_version: "{{ 'main' if matrix_alertmanager_receiver_version == 'main' else matrix_alertmanager_receiver_version }}"
 matrix_alertmanager_receiver_container_src_path: "{{ matrix_alertmanager_receiver_base_path }}/container-src"
 
-matrix_alertmanager_receiver_container_image: "{{ matrix_alertmanager_receiver_container_image_name_prefix }}metio/matrix-alertmanager-receiver:{{ matrix_alertmanager_receiver_container_image_tag }}"
-matrix_alertmanager_receiver_container_image_name_prefix: "{{ 'localhost/' if matrix_alertmanager_receiver_container_image_self_build else matrix_alertmanager_receiver_container_image_registry_prefix }}"
+matrix_alertmanager_receiver_container_image: "{{ matrix_alertmanager_receiver_container_image_registry_prefix }}metio/matrix-alertmanager-receiver:{{ matrix_alertmanager_receiver_container_image_tag }}"
 matrix_alertmanager_receiver_container_image_tag: "{{ matrix_alertmanager_receiver_version }}"
 matrix_alertmanager_receiver_container_image_force_pull: "{{ matrix_alertmanager_receiver_container_image.endswith(':main') }}"
-matrix_alertmanager_receiver_container_image_registry_prefix: docker.io/
+matrix_alertmanager_receiver_container_image_registry_prefix: "{{ matrix_alertmanager_receiver_container_image_registry_prefix_upstream }}"
+matrix_alertmanager_receiver_container_image_registry_prefix_upstream: "{{ matrix_alertmanager_receiver_container_image_registry_prefix_upstream_default }}"
+matrix_alertmanager_receiver_container_image_registry_prefix_upstream_default: "docker.io/"
 
 # The base container network. It will be auto-created by this role if it doesn't exist already.
 matrix_alertmanager_receiver_container_network: ''

roles/custom/matrix-alertmanager-receiver/tasks/validate_config.yml

@@ -12,3 +12,11 @@
     - {'name': 'matrix_alertmanager_receiver_container_network', when: true}
     - {'name': 'matrix_alertmanager_receiver_metrics_proxying_hostname', when: "{{ matrix_alertmanager_receiver_metrics_proxying_enabled }}"}
     - {'name': 'matrix_alertmanager_receiver_metrics_proxying_path_prefix', when: "{{ matrix_alertmanager_receiver_metrics_proxying_enabled }}"}
+
+- name: (Deprecation) Catch and report renamed matrix-alertmanager-receiver variables
+  ansible.builtin.fail:
+    msg: >-
+      The variable `{{ item.old }}` is deprecated. Please use `{{ item.new }}` instead.
+  when: "item.old in vars"
+  with_items:
+    - {'old': 'matrix_alertmanager_receiver_container_image_name_prefix', 'new': 'matrix_alertmanager_receiver_container_image_registry_prefix'}