Implementation of MSC2314 (#6176)

tests/utils.py

@@ -109,6 +109,7 @@ def default_config(name, parse=False):
     """
     config_dict = {
         "server_name": name,
+        "send_federation": False,
         "media_store_path": "media",
         "uploads_path": "uploads",
         # the test signing key is just an arbitrary ed25519 key to keep the config