reorganise samples folder

samples/NotificationFlyoutSample.Host/Program.cs

@@ -0,0 +1,18 @@
+using System;
+
+namespace NotificationFlyoutSample.Host
+{
+    public class Program
+    {
+        [STAThread()]
+        public static void Main()
+        {
+            using (new NotificationFlyoutSample.App())
+            {
+                var app = new App();
+                new SampleNotificationFlyout();
+                app.Run();
+            }
+        }
+    }
+}