Revert "Bungee join / part messages"

This reverts commit 7108bd4deb.

api/src/main/java/net/md_5/bungee/api/ProxyServer.java

@@ -247,11 +247,4 @@ public abstract class ProxyServer
      * @return the server's {@link AsyncHttpClient} instance
      */
     public abstract AsyncHttpClient getHttpClient();
-
-    /**
-     * Send a message to all connected players.
-     *
-     * @param message the message to send
-     */
-    public abstract void broadcast(String message);
 }