Remove: old server announcement to Master Server

As we now use the Game Coordinator for announcements, there is no
longer a need to use the Master Server for this.

src/network/network_udp.h

@@ -16,8 +16,6 @@ void NetworkUDPInitialize();
 void NetworkUDPSearchGame();
 void NetworkUDPQueryMasterServer();
 void NetworkUDPQueryServer(const std::string &connection_string, bool manually = false);
-void NetworkUDPAdvertise();
-void NetworkUDPRemoveAdvertise(bool blocking);
 void NetworkUDPClose();
 void NetworkUDPServerListen();
 void NetworkBackgroundUDPLoop();