bridge-mautrix-signal: add option for creating non-federated rooms

roles/matrix-bridge-mautrix-signal/defaults/main.yml

@@ -56,6 +56,10 @@ matrix_mautrix_signal_homeserver_token: ''
 
 matrix_mautrix_signal_appservice_bot_username: signalbot
 
+# Whether or not created rooms should have federation enabled.
+# If false, created portal rooms will never be federated.
+matrix_mautrix_signal_federate_rooms: true
+
 # Database-related configuration fields
 #
 # This bridge only supports postgres.