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-common-after/defaults/main.yml

@@ -0,0 +1,17 @@
+---
+# Specifies how long to wait between starting systemd services and checking if they're started.
+#
+# A too low value may lead to a failure, as services may not have enough time to start and potentially fail.
+#
+# A value higher than 30 seconds (or any multiple of that) may also not work well, because a failing systemd service
+# auto-restarts after 30 seconds (`RestartSec=30` in systemd service files).
+# Checking if a service is running right after it had potentially restarted in such a way will lead us to
+# thinking it's running, while it's merely starting again (and likely to fail again, given that it already did once).
+#
+# All of the services we manage are also started sequentially, which in itself can take a long time.
+# There may be a ~10 second (or even larger) interval between starting the first service and starting the last one.
+# This makes it even harder to pick a correct value. Such a 10 second gap and a waiting time of 20 seconds will
+# put us right at the "dangerous" 30-second mark.
+#
+# We can try to measure this gap and adjust our waiting time accordingly, but we currently don't.
+matrix_common_after_systemd_service_start_wait_for_timeout_seconds: 15

roles/custom/matrix-common-after/tasks/dump_runtime_results.yml

@@ -0,0 +1,7 @@
+---
+# Ansible outputs the message in the `item=` field.
+# It's unnecessary to output it again in the actual message, so we don't.
+- ansible.builtin.debug:
+    msg: ""
+  with_items: "{{ matrix_playbook_runtime_results }}"
+  when: "matrix_playbook_runtime_results is defined and matrix_playbook_runtime_results | length > 0"

roles/custom/matrix-common-after/tasks/main.yml

@@ -0,0 +1,19 @@
+---
+
+- ansible.builtin.import_tasks: "{{ role_path }}/tasks/start.yml"
+  when: run_start | bool
+  tags:
+    - start
+
+- ansible.builtin.import_tasks: "{{ role_path }}/tasks/stop.yml"
+  when: run_stop | bool
+  tags:
+    - stop
+
+- ansible.builtin.import_tasks: "{{ role_path }}/tasks/dump_runtime_results.yml"
+  tags:
+    - always
+
+- ansible.builtin.import_tasks: "{{ role_path }}/tasks/run_docker_prune.yml"
+  tags:
+    - run-docker-prune

roles/custom/matrix-common-after/tasks/run_docker_prune.yml

@@ -0,0 +1,7 @@
+---
+
+- name: Run Docker System Prune
+  ansible.builtin.command:
+    cmd: "{{ matrix_host_command_docker }} system prune -a -f"
+  register: matrix_common_after_docker_prune_result
+  changed_when: matrix_common_after_docker_prune_result.rc == 0

roles/custom/matrix-common-after/tasks/start.yml

@@ -0,0 +1,73 @@
+---
+
+- name: Determine whether we should make services autostart
+  ansible.builtin.set_fact:
+    matrix_services_autostart_enabled_bool: "{{ true if matrix_services_autostart_enabled | default('') == '' else matrix_services_autostart_enabled | bool }}"
+
+- name: Ensure systemd is reloaded
+  ansible.builtin.service:
+    daemon_reload: true
+
+- name: Ensure Matrix services are stopped
+  ansible.builtin.service:
+    name: "{{ item }}"
+    state: stopped
+  with_items: "{{ matrix_systemd_services_list }}"
+  when: not ansible_check_mode
+
+- name: Ensure Matrix services are started
+  ansible.builtin.service:
+    name: "{{ item }}"
+    enabled: "{{ matrix_services_autostart_enabled_bool }}"
+    state: started
+  with_items: "{{ matrix_systemd_services_list }}"
+  when: not ansible_check_mode
+
+# If we check service state immediately, we may succeed,
+# because it takes some time for the service to attempt to start and actually fail.
+#
+# Waiting too long (30s) may not work for a similar reason,
+# as we may run into systemd's automatic restart logic retrying the service.
+- name: Wait a bit, so that services can start (or fail)
+  ansible.builtin.wait_for:
+    timeout: "{{ matrix_common_after_systemd_service_start_wait_for_timeout_seconds }}"
+  delegate_to: 127.0.0.1
+  become: false
+
+- when: "ansible_distribution != 'Archlinux'"
+  block:
+    - name: Populate service facts
+      ansible.builtin.service_facts:
+
+    - name: Fail if service isn't detected to be running
+      ansible.builtin.fail:
+        msg: >-
+          {{ item }} was not detected to be running.
+          It's possible that there's a configuration problem or another service on your server interferes with it (uses the same ports, etc.).
+          Try running `systemctl status {{ item }}` and `journalctl -fu {{ item }}` on the server to investigate.
+          If you're on a slow or overloaded server, it may be that services take a longer time to start and that this error is a false-positive.
+          You can consider raising the value of the `matrix_common_after_systemd_service_start_wait_for_timeout_seconds` variable.
+          See `roles/custom/matrix-common-after/defaults/main.yml` for more details about that.
+      with_items: "{{ matrix_systemd_services_list }}"
+      when:
+        - "item.endswith('.service') and (ansible_facts.services[item] | default(none) is none or ansible_facts.services[item].state != 'running')"
+
+- when: "ansible_distribution == 'Archlinux'"
+  block:
+    # Currently there is a bug in ansible that renders is incompatible with systemd.
+    # service_facts is not collecting the data successfully.
+    # Therefore iterating here manually
+    - name: Fetch systemd information
+      ansible.builtin.systemd:
+        name: "{{ item }}"
+      register: systemdstatus
+      with_items: "{{ matrix_systemd_services_list }}"
+
+    - name: Fail if service isn't detected to be running
+      ansible.builtin.fail:
+        msg: >-
+          {{ item.item }} was not detected to be running.
+          It's possible that there's a configuration problem or another service on your server interferes with it (uses the same ports, etc.).
+          Try running `systemctl status {{ item.item }}` and `journalctl -fu {{ item.item }}` on the server to investigate.
+      with_items: "{{ systemdstatus.results }}"
+      when: "item.status['ActiveState'] != 'active'"

roles/custom/matrix-common-after/tasks/stop.yml

@@ -0,0 +1,7 @@
+---
+
+- name: Ensure Matrix services stopped
+  ansible.builtin.service:
+    name: "{{ item }}"
+    state: stopped
+  with_items: "{{ matrix_systemd_services_list }}"