Add support for static files.

Source/MQTTnet.Server/Web/wwwroot/Hello.txt

@@ -0,0 +1 @@
+World

Source/MQTTnet.Server/Web/wwwroot/pahoJS_Test.html

@@ -0,0 +1,41 @@
+<html>
+
+<head>
+    <title>paho JS Example</title>
+
+    <script src="https://cdnjs.cloudflare.com/ajax/libs/paho-mqtt/1.0.1/mqttws31.js" type="text/javascript"></script>
+
+    <script type="text/javascript">
+        var mqttClient = new Paho.MQTT.Client("localhost", 80, "/mqtt", "pahoJS_client");
+        mqttClient.onConnectionLost = onConnectionLost;
+        mqttClient.onMessageArrived = onMessageArrived;
+        mqttClient.connect({ onSuccess: onConnect });
+
+        function onConnect() {
+            console.log("MQTT client connected");
+            mqttClient.subscribe("pahoJS_subscription");
+        }
+
+        function onConnectionLost(responseObject) {
+            if (responseObject.errorCode !== 0) {
+                console.log("onConnectionLost:" + responseObject.errorMessage);
+            }
+        }
+
+        function onMessageArrived(message) {
+            console.log("onMessageArrived:" + message.payloadString);
+        }
+        function buttonClick() {
+            message = new Paho.MQTT.Message("Hello");
+            message.destinationName = "pahoJS_topic";
+            mqttClient.send(message);
+        }
+    </script>
+
+</head>
+
+<body>
+    <button onclick="buttonClick()">Publish</button>
+</body>
+
+</html>