Remove obsolete files.

Frameworks/MQTTnet.NetStandard/Server/MqttServerEventDispatcher.cs

@@ -1,14 +0,0 @@
-using System;
-
-namespace MQTTnet.Server
-{
-    public class MqttServerEventDispatcher
-    {
-        public event EventHandler<MqttClientConnectedEventArgs> ClientConnected;
-        public event EventHandler<MqttClientDisconnectedEventArgs> ClientDisconnected;
-        public event EventHandler<MqttClientSubscribedTopicEventArgs> ClientSubscribedTopic;
-        public event EventHandler<MqttClientUnsubscribedTopicEventArgs> ClientUnsubscribedTopic;
-
-        public event EventHandler<MqttApplicationMessageReceivedEventArgs> ApplicationMessageReceived;
-    }
-}