Synchronous invites (#1273)

* Refactor invites to be synchronous

* Fix synchronous invites

* Fix client API return type for send invite error

* Linter

* Restore PerformError on rsAPI.PerformInvite

* Update sytest-whitelist

* Don't override PerformError with normal errors

* Fix error passing

* Un-whitelist a couple of tests

* Update sytest-whitelist

* Try to handle multiple invite rejections better

* nolint

* Update gomatrixserverlib

* Fix /v1/invite test

* Remove replace from go.mod

federationapi/routing/routing.go

@@ -90,16 +90,10 @@ func Setup(
 					JSON: jsonerror.Forbidden("Forbidden by server ACLs"),
 				}
 			}
-			res := InviteV1(
+			return InviteV1(
 				httpReq, request, vars["roomID"], vars["eventID"],
 				cfg, rsAPI, keys,
 			)
-			return util.JSONResponse{
-				Code: res.Code,
-				JSON: []interface{}{
-					res.Code, res.JSON,
-				},
-			}
 		},
 	)).Methods(http.MethodPut, http.MethodOptions)