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-postgres-backup/templates/env-postgres-backup.j2

@@ -0,0 +1,12 @@
+#jinja2: lstrip_blocks: "True"
+POSTGRES_USER={{ matrix_postgres_backup_connection_username }}
+POSTGRES_PASSWORD={{ matrix_postgres_backup_connection_password }}
+POSTGRES_HOST={{ matrix_postgres_backup_connection_hostname }}
+POSTGRES_DB={{ matrix_postgres_backup_databases|join(', ') }}
+POSTGRES_EXTRA_OPTS={{ matrix_postgres_backup_extra_opts }}
+SCHEDULE={{ matrix_postgres_backup_schedule }}
+BACKUP_KEEP_DAYS={{ matrix_postgres_backup_keep_days }}
+BACKUP_KEEP_WEEKS={{ matrix_postgres_backup_keep_weeks }}
+BACKUP_KEEP_MONTHS={{ matrix_postgres_backup_keep_months }}
+HEALTHCHECK_PORT={{ matrix_postgres_backup_healthcheck_port }}
+POSTGRES_PORT={{ matrix_postgres_backup_connection_port }}

roles/custom/matrix-postgres-backup/templates/systemd/matrix-postgres-backup.service.j2

@@ -0,0 +1,31 @@
+#jinja2: lstrip_blocks: "True"
+[Unit]
+Description=Automatic Backup of  Matrix Postgres server
+After=docker.service
+Requires=docker.service
+DefaultDependencies=no
+
+[Service]
+Type=simple
+Environment="HOME={{ matrix_systemd_unit_home_path }}"
+ExecStartPre=-{{ matrix_host_command_docker }} stop matrix-postgres-backup
+ExecStartPre=-{{ matrix_host_command_sh }} -c '{{ matrix_host_command_docker }} rm matrix-postgres-backup 2>/dev/null || true'
+
+ExecStart={{ matrix_host_command_docker }} run --rm --name matrix-postgres-backup \
+			--log-driver=none \
+			--user={{ matrix_user_uid }}:{{ matrix_user_gid }} \
+			--cap-drop=ALL \
+			--read-only \
+			--network={{ matrix_docker_network }} \
+			--env-file={{ matrix_postgres_backup_path }}/env-postgres-backup \
+			--mount type=bind,src={{ matrix_postgres_backup_path }},dst=/backups \
+			{{ matrix_postgres_backup_docker_image_to_use }}
+
+ExecStop=-{{ matrix_host_command_docker }} stop matrix-postgres-backup
+ExecStop=-{{ matrix_host_command_sh }} -c '{{ matrix_host_command_docker }} rm matrix-postgres-backup 2>/dev/null || true'
+Restart=always
+RestartSec=30
+SyslogIdentifier=matrix-postgres-backup
+
+[Install]
+WantedBy=multi-user.target