Try to avoid Docker logs growing too much for one-off containers

We recently had a report of the Postgres backup container's log file
growing the size of /var/lib/docker until it ran out of disk space.

Trying to prevent similar problems in the future.

roles/matrix-postgres/tasks/import_sqlite_db.yml

@@ -74,6 +74,7 @@
     docker run
     --rm
     --name=matrix-synapse-migrate
+    --log-driver=none
     --user={{ matrix_user_uid }}:{{ matrix_user_gid }}
     --cap-drop=ALL
     --network={{ matrix_docker_network }}