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-dynamic-dns/tasks/validate_config.yml

@@ -1,12 +1,12 @@
 ---
 
-- name: Fail if no configurations specified
+- name: Fail if no matrix-dynamic-dns configurations specified
   ansible.builtin.fail:
     msg: >-
       You need to define at least one configuration in `matrix_dynamic_dns_domain_configurations` for using matrix-dynamic-dns.
   when: "matrix_dynamic_dns_domain_configurations | length == 0"
 
-- name: Fail if required settings not defined in configuration blocks
+- name: Fail if required matrix-dynamic-dns settings not defined in configuration blocks
   ansible.builtin.fail:
     msg: >-
       One of the configurations in matrix_dynamic_dns_domain_configurations is missing a required key (domain, provider, protocol).
@@ -15,10 +15,18 @@
   loop_control:
     loop_var: configuration
 
-- name: Fail if required mautrix-dynamic-dns settings not defined
+- name: Fail if required matrix-dynamic-dns settings not defined
   ansible.builtin.fail:
     msg: >-
       You need to define a required configuration setting (`{{ item.name }}`).
   when: "item.when | bool and vars[item.name] == ''"
   with_items:
     - {'name': 'matrix_dynamic_dns_container_network', when: true}
+
+- name: (Deprecation) Catch and report renamed matrix-dynamic-dns 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_dynamic_dns_container_image_name_prefix', 'new': 'matrix_dynamic_dns_docker_image_registry_prefix'}