Add Synapse Maintenance docs and synapse-janitor integration

roles/matrix-base/defaults/main.yml

@@ -46,6 +46,8 @@ matrix_well_known_matrix_server_enabled: true
 run_postgres_import: true
 run_postgres_upgrade: true
 run_postgres_import_sqlite_db: true
+run_postgres_synapse_janitor: true
+run_postgres_vacuum: true
 run_synapse_register_user: true
 run_synapse_update_user_password: true
 run_synapse_import_media_store: true