Move roles/matrix* to roles/custom/matrix*

This paves the way for installing other roles into `roles/galaxy` using `ansible-galaxy`,
similar to how it's done in:

- https://github.com/spantaleev/gitea-docker-ansible-deploy
- https://github.com/spantaleev/nextcloud-docker-ansible-deploy

In the near future, we'll be removing a lot of the shared role code from here
and using upstream roles for it. Some of the core `matrix-*` roles have
already been extracted out into other reusable roles:

- https://github.com/devture/com.devture.ansible.role.postgres
- https://github.com/devture/com.devture.ansible.role.systemd_docker_base
- https://github.com/devture/com.devture.ansible.role.timesync
- https://github.com/devture/com.devture.ansible.role.vars_preserver
- https://github.com/devture/com.devture.ansible.role.playbook_runtime_messages
- https://github.com/devture/com.devture.ansible.role.playbook_help

We just need to migrate to those.

roles/custom/matrix-registration/tasks/list_tokens.yml

@@ -0,0 +1,31 @@
+---
+
+- name: Call matrix-registration list all tokens API
+  ansible.builtin.uri:
+    url: "{{ matrix_registration_api_token_endpoint }}"
+    follow_redirects: none
+    validate_certs: "{{ matrix_registration_api_validate_certs }}"
+    headers:
+      Content-Type: application/json
+      Authorization: "SharedSecret {{ matrix_registration_admin_secret }}"
+    method: GET
+    body_format: json
+  check_mode: false
+  register: matrix_registration_api_result
+
+- ansible.builtin.set_fact:
+    matrix_registration_api_result_message: >-
+      matrix-registration result:
+
+      {{ matrix_registration_api_result.json | to_nice_json }}
+  check_mode: false
+
+- name: Inject result message into matrix_playbook_runtime_results
+  ansible.builtin.set_fact:
+    matrix_playbook_runtime_results: |
+      {{
+        matrix_playbook_runtime_results | default([])
+        +
+        [matrix_registration_api_result_message]
+      }}
+  check_mode: false