Roomserver perform join (#1001)

* Add PerformJoin template

* Try roomserver perform join

* Send correct server name to FS API

* Pass through content, try to handle multiple server names

* Fix local server checks

* Don't refer to non-existent error

* Add directory lookups of aliases

* Remove unneeded parameters

* Don't repeat join events into the roomserver

* Unmarshal the content, that would help

* Check if the user is already in the room in the fedeationapi too

* Return incompatible room version error

* Use Membership, don't try more servers than needed

* Review comments, make FS API take list of servernames, dedupe them, break out of loop properly on success

* Tweaks

clientapi/routing/routing.go

@@ -100,8 +100,7 @@ func Setup(
 				return util.ErrorResponse(err)
 			}
 			return JoinRoomByIDOrAlias(
-				req, device, vars["roomIDOrAlias"], cfg, federation, producer,
-				rsAPI, federationSender, keyRing, accountDB,
+				req, device, rsAPI, vars["roomIDOrAlias"],
 			)
 		}),
 	).Methods(http.MethodPost, http.MethodOptions)