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-appservice-discord/tasks/setup_install.yml

@@ -0,0 +1,121 @@
+---
+
+- ansible.builtin.set_fact:
+    matrix_appservice_discord_requires_restart: false
+
+- when: "matrix_appservice_discord_database_engine == 'postgres'"
+  block:
+    - name: Check if an SQLite database already exists
+      ansible.builtin.stat:
+        path: "{{ matrix_appservice_discord_sqlite_database_path_local }}"
+      register: matrix_appservice_discord_sqlite_database_path_local_stat_result
+
+    - when: "matrix_appservice_discord_sqlite_database_path_local_stat_result.stat.exists | bool"
+      block:
+        - ansible.builtin.set_fact:
+            matrix_postgres_db_migration_request:
+              src: "{{ matrix_appservice_discord_sqlite_database_path_local }}"
+              dst: "{{ matrix_appservice_discord_database_connString }}"
+              caller: "{{ role_path | basename }}"
+              engine_variable_name: 'matrix_appservice_discord_database_engine'
+              engine_old: 'sqlite'
+              systemd_services_to_stop: ['matrix-appservice-discord.service']
+
+        - ansible.builtin.import_role:
+            name: custom/matrix-postgres
+            tasks_from: migrate_db_to_postgres
+
+        - ansible.builtin.set_fact:
+            matrix_appservice_discord_requires_restart: true
+
+- name: Ensure Appservice Discord image is pulled
+  community.docker.docker_image:
+    name: "{{ matrix_appservice_discord_docker_image }}"
+    source: "{{ 'pull' if ansible_version.major > 2 or ansible_version.minor > 7 else omit }}"
+    force_source: "{{ matrix_appservice_discord_docker_image_force_pull if ansible_version.major > 2 or ansible_version.minor >= 8 else omit }}"
+    force: "{{ omit if ansible_version.major > 2 or ansible_version.minor >= 8 else matrix_appservice_discord_docker_image_force_pull }}"
+  register: result
+  retries: "{{ matrix_container_retries_count }}"
+  delay: "{{ matrix_container_retries_delay }}"
+  until: result is not failed
+
+- name: Ensure AppService Discord paths exist
+  ansible.builtin.file:
+    path: "{{ item }}"
+    state: directory
+    mode: 0750
+    owner: "{{ matrix_user_username }}"
+    group: "{{ matrix_user_groupname }}"
+  with_items:
+    - "{{ matrix_appservice_discord_base_path }}"
+    - "{{ matrix_appservice_discord_config_path }}"
+    - "{{ matrix_appservice_discord_data_path }}"
+
+- name: Check if an old database file already exists
+  ansible.builtin.stat:
+    path: "{{ matrix_appservice_discord_base_path }}/discord.db"
+  register: matrix_appservice_discord_stat_db
+
+- name: (Data relocation) Ensure matrix-appservice-discord.service is stopped
+  ansible.builtin.service:
+    name: matrix-appservice-discord
+    state: stopped
+    enabled: false
+    daemon_reload: true
+  failed_when: false
+  when: "matrix_appservice_discord_stat_db.stat.exists"
+
+- name: (Data relocation) Move AppService Discord discord.db file to ./data directory
+  ansible.builtin.command: "mv {{ matrix_appservice_discord_base_path }}/{{ item }} {{ matrix_appservice_discord_data_path }}/{{ item }}"
+  with_items:
+    - discord.db
+    - user-store.db
+    - room-store.db
+  when: "matrix_appservice_discord_stat_db.stat.exists"
+
+- name: Ensure AppService Discord config.yaml installed
+  ansible.builtin.copy:
+    content: "{{ matrix_appservice_discord_configuration | to_nice_yaml(indent=2, width=999999) }}"
+    dest: "{{ matrix_appservice_discord_config_path }}/config.yaml"
+    mode: 0644
+    owner: "{{ matrix_user_username }}"
+    group: "{{ matrix_user_groupname }}"
+
+- name: Ensure AppService Discord registration.yaml installed
+  ansible.builtin.copy:
+    content: "{{ matrix_appservice_discord_registration | to_nice_yaml(indent=2, width=999999) }}"
+    dest: "{{ matrix_appservice_discord_config_path }}/registration.yaml"
+    mode: 0644
+    owner: "{{ matrix_user_username }}"
+    group: "{{ matrix_user_groupname }}"
+
+# If `matrix_appservice_discord_client_id` hasn't changed, the same invite link would be generated.
+# We intentionally suppress Ansible changes.
+- name: Generate AppService Discord invite link
+  ansible.builtin.shell: >-
+    {{ matrix_host_command_docker }} run --rm --name matrix-appservice-discord-link-gen
+    --user={{ matrix_user_uid }}:{{ matrix_user_gid }}
+    --cap-drop=ALL
+    --mount type=bind,src={{ matrix_appservice_discord_config_path }},dst=/cfg
+    -w /cfg
+    {{ matrix_appservice_discord_docker_image }}
+    /bin/sh -c "node /build/tools/addbot.js > /cfg/invite_link"
+  changed_when: false
+
+- name: Ensure matrix-appservice-discord.service installed
+  ansible.builtin.template:
+    src: "{{ role_path }}/templates/systemd/matrix-appservice-discord.service.j2"
+    dest: "{{ matrix_systemd_path }}/matrix-appservice-discord.service"
+    mode: 0644
+  register: matrix_appservice_discord_systemd_service_result
+
+- name: Ensure systemd reloaded after matrix-appservice-discord.service installation
+  ansible.builtin.service:
+    daemon_reload: true
+  when: "matrix_appservice_discord_systemd_service_result.changed"
+
+- name: Ensure matrix-appservice-discord.service restarted, if necessary
+  ansible.builtin.service:
+    name: "matrix-appservice-discord.service"
+    state: restarted
+  when: "matrix_appservice_discord_requires_restart | bool"