Remove TLS support for UWP servers because Framework does not support it.

MQTTnet.Core/Client/MqttClientTlsOptions.cs

@@ -0,0 +1,13 @@
+using System.Collections.Generic;
+
+namespace MQTTnet.Core.Client
+{
+    public sealed class MqttClientTlsOptions
+    {
+        public bool UseTls { get; set; }
+
+        public bool CheckCertificateRevocation { get; set; }
+
+        public List<byte[]> Certificates { get; set; }
+    }
+}