Separate Facebook bridge configuration and data

Using a separate directory allows easier backups
(only need to back up the Ansible playbook configuration and the
bridge's `./data` directory).

The playbook takes care of migrating an existing database file
from the base directory into the `./data` directory.

In the future, we can also mount the configuration read-only,
to ensure the bridge won't touch it.
For now, mautrix-facebook is keen on rebuilding the `config.yaml`
file on startup though, so this will have to wait.

roles/matrix-bridge-mautrix-facebook/templates/systemd/matrix-mautrix-facebook.service.j2

@@ -17,9 +17,10 @@ ExecStartPre=/usr/bin/docker run --rm --name matrix-mautrix-facebook-db \
 			--log-driver=none \
 			--user={{ matrix_user_uid }}:{{ matrix_user_gid }} \
 			--cap-drop=ALL \
-			-v {{ matrix_mautrix_facebook_base_path }}:/data:z \
+			-v {{ matrix_mautrix_facebook_data_path }}:/data:z \
+			-v {{ matrix_mautrix_facebook_config_path }}:/config:z \
 			{{ matrix_mautrix_facebook_docker_image }} \
-			alembic -x config=/data/config.yaml upgrade head
+			alembic -x config=/config/config.yaml upgrade head
 
 # Intentional delay, so that the homeserver (we likely depend on) can manage to start.
 ExecStartPre=/bin/sleep 5
@@ -29,12 +30,13 @@ ExecStart=/usr/bin/docker run --rm --name matrix-mautrix-facebook \
 			--user={{ matrix_user_uid }}:{{ matrix_user_gid }} \
 			--cap-drop=ALL \
 			--network={{ matrix_docker_network }} \
-			-v {{ matrix_mautrix_facebook_base_path }}:/data:z \
+			-v {{ matrix_mautrix_facebook_data_path }}:/data:z \
+			-v {{ matrix_mautrix_facebook_config_path }}:/config:z \
 			{% for arg in matrix_mautrix_facebook_container_extra_arguments %}
 			{{ arg }} \
 			{% endfor %}
 			{{ matrix_mautrix_facebook_docker_image }} \
-			python3 -m mautrix_facebook -c /data/config.yaml
+			python3 -m mautrix_facebook -c /config/config.yaml
 
 ExecStop=-/usr/bin/docker kill matrix-mautrix-facebook
 ExecStop=-/usr/bin/docker rm matrix-mautrix-facebook