Moved application code to the Application layer

Imported Win10 project
Code cleanup
WIP - Use common UWP services for Win8.1 and Win10

ModernKeePass10/Views/Old/MainPage.xaml.cs

@@ -0,0 +1,40 @@
+using Windows.Storage;
+using Windows.UI.Xaml.Controls;
+using Windows.UI.Xaml.Navigation;
+using ModernKeePass.ViewModels;
+using ModernKeePass.ViewModels.ListItems;
+
+// The Blank Page item template is documented at http://go.microsoft.com/fwlink/?LinkId=234238
+
+namespace ModernKeePass.Views
+{
+    /// <summary>
+    /// An empty page that can be used on its own or navigated to within a Frame.
+    /// </summary>
+    public sealed partial class MainPage
+    {
+        public new MainVm Model => (MainVm)DataContext;
+        
+        public MainPage()
+        {
+            InitializeComponent();
+            ListView = MenuListView;
+            ListViewSource = MenuItemsSource;
+        }
+
+        private new void ListView_SelectionChanged(object sender, SelectionChangedEventArgs e)
+        {
+            base.ListView_SelectionChanged(sender, e);
+
+            if (!(Model.SelectedItem is MainMenuItemViewModel selectedItem)) MenuFrame.Navigate(typeof(WelcomePage));
+            else selectedItem.Destination.Navigate(selectedItem.PageType, selectedItem.Parameter);
+        }
+        
+        protected override void OnNavigatedTo(NavigationEventArgs e)
+        {
+            base.OnNavigatedTo(e);
+            var file = e.Parameter as StorageFile;
+            DataContext = new MainVm(Frame, MenuFrame, file);
+        }
+    }
+}