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-bridge-mautrix-twitter/tasks/init.yml

@@ -0,0 +1,29 @@
+---
+
+- ansible.builtin.set_fact:
+    matrix_systemd_services_list: "{{ matrix_systemd_services_list + ['matrix-mautrix-twitter.service'] }}"
+  when: matrix_mautrix_twitter_enabled | bool
+
+# If the matrix-synapse role is not used, these variables may not exist.
+- ansible.builtin.set_fact:
+    matrix_homeserver_container_runtime_injected_arguments: >
+      {{
+        matrix_homeserver_container_runtime_injected_arguments | default([])
+        +
+        ["--mount type=bind,src={{ matrix_mautrix_twitter_config_path }}/registration.yaml,dst=/matrix-mautrix-twitter-registration.yaml,ro"]
+      }}
+
+    matrix_homeserver_app_service_runtime_injected_config_files: >
+      {{
+        matrix_homeserver_app_service_runtime_injected_config_files | default([])
+        +
+        ["/matrix-mautrix-twitter-registration.yaml"]
+      }}
+  when: matrix_mautrix_twitter_enabled | bool
+
+# ansible lower than 2.8, does not support docker_image build parameters
+# for self buildig it is explicitly needed, so we rather fail here
+- name: Fail if running on Ansible lower than 2.8 and trying self building
+  ansible.builtin.fail:
+    msg: "To self build Mautrix Twitter image, you should usa ansible 2.8 or higher. E.g. pip contains such packages."
+  when: "ansible_version.major == 2 and ansible_version.minor < 8 and matrix_mautrix_twitter_container_image_self_build"