Change "who is EmbyServer?" and other udp responders to jellyfin alternatives. (#400)

* replace emby server udp responders with Jellyfin responders

* remove unnecessary second udp responder

* readdemby listener

* use false instead of true dunni why but it was like that sooo

Emby.Server.Implementations/Udp/UdpServer.cs

@@ -40,6 +40,7 @@ namespace Emby.Server.Implementations.Udp
             _json = json;
             _socketFactory = socketFactory;
 
+            AddMessageResponder("who is JellyfinServer?", true, RespondToV2Message);
             AddMessageResponder("who is EmbyServer?", true, RespondToV2Message);
             AddMessageResponder("who is MediaBrowserServer_v2?", false, RespondToV2Message);
         }