Add Blazor test app.

Tests/MQTTnet.Test.BlazorApp/Server/Pages/Shared/_Layout.cshtml

@@ -0,0 +1,20 @@
+<!DOCTYPE html>
+<html>
+
+<head>
+    <meta charset="utf-8" />
+    <meta name="viewport" content="width=device-width, initial-scale=1.0, maximum-scale=1.0, user-scalable=no" />
+    <title>@ViewBag.Title</title>
+    <link href="~/css/bootstrap/bootstrap.min.css" rel="stylesheet" />
+    <link href="~/css/app.css" rel="stylesheet" />
+</head>
+
+<body>
+    <div class="main">
+        <div class="content px-4">
+            @RenderBody()
+        </div>
+    </div>
+</body>
+
+</html>