Rename variable (matrix_bot_matrix_registration_bot_matrix_homeserver_url -> matrix_bot_matrix_registration_bot_api_base_url)

We were overriding the `matrix_bot_matrix_registration_bot_matrix_homeserver_url` variable via `group_vars/matrix_servers`
to point it to the container-local homeserver URL, but this variable was not being used at all.

The actual variable name (which was being used) is `matrix_bot_matrix_registration_bot_api_base_url`.

Fixes #3898

Author: spantaleev

group_vars/matrix_servers

@@ -2737,7 +2737,7 @@ matrix_bot_matrix_registration_bot_container_additional_networks_auto: |-
     ([] if matrix_addons_homeserver_container_network == '' else [matrix_addons_homeserver_container_network])
   }}
 
-matrix_bot_matrix_registration_bot_matrix_homeserver_url: "{{ matrix_addons_homeserver_client_api_url }}"
+matrix_bot_matrix_registration_bot_api_base_url: "{{ matrix_addons_homeserver_client_api_url }}"
 
 ######################################################################
 #

roles/custom/matrix-bot-matrix-registration-bot/defaults/main.yml

@@ -57,5 +57,3 @@ matrix_bot_matrix_registration_bot_systemd_wanted_services_list: []
 matrix_bot_matrix_registration_bot_matrix_user_id_localpart: "bot.matrix-registration-bot"
 
 matrix_bot_matrix_registration_bot_matrix_user_id: '@{{ matrix_bot_matrix_registration_bot_matrix_user_id_localpart }}:{{ matrix_domain }}'
-
-matrix_bot_matrix_registration_bot_matrix_homeserver_url: ""

roles/custom/matrix-bot-matrix-registration-bot/tasks/validate_config.yml

@@ -7,12 +7,14 @@
   when: "vars[item] == ''"
   with_items:
     - "matrix_bot_matrix_registration_bot_bot_password"
-    - "matrix_bot_matrix_registration_bot_matrix_homeserver_url"
+    - "matrix_bot_matrix_registration_bot_api_base_url"
 
-- name: (Deprecation) Catch and report old settings
+- name: (Deprecation) Catch and report renamed settings
   ansible.builtin.fail:
     msg: >-
-      Your configuration contains a variable, which is deprecated - Please check the documentation on how to configure the matrix-registration-bot.
-  when: "item in vars"
+      Your configuration contains a variable, which now has a different name.
+      Please change your configuration to rename the variable (`{{ item.old }}` -> `{{ item.new }}`).
+  when: "item.old in vars"
   with_items:
-    - "matrix_bot_matrix_registration_bot_bot_access_token"
+    - {'old': 'matrix_bot_matrix_registration_bot_bot_access_token', 'new': '<removed>'}
+    - {'old': 'matrix_bot_matrix_registration_bot_matrix_homeserver_url', 'new': 'matrix_bot_matrix_registration_bot_api_base_url'}