Moved application code to the Application layer

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

ModernKeePass10/Views/SettingsPage10.xaml.cs

@@ -0,0 +1,67 @@
+using System;
+using System.Collections.Generic;
+using System.Linq;
+using Windows.UI.Xaml;
+using Windows.UI.Xaml.Controls;
+using Windows.ApplicationModel.Core;
+using ModernKeePass.ViewModels;
+using ModernKeePass.Views.SettingsPageFrames;
+
+namespace ModernKeePass.Views
+{
+    public partial class SettingsPage10
+    {
+        private SettingsViewModel ViewModel { get; }
+
+        private readonly IList<(string Tag, Type Page)> _pages = new List<(string Tag, Type Page)>
+        {
+            ("welcome", typeof(SettingsWelcomePage)),
+            ("new", typeof(SettingsNewDatabasePage)),
+            ("save", typeof(SettingsSavePage)),
+            ("general", typeof(SettingsDatabasePage)),
+            ("security", typeof(SettingsSecurityPage))
+        };
+
+        public SettingsPage10()
+        {
+            InitializeComponent();
+            ViewModel = new SettingsViewModel();
+            SetTitleBar();
+        }
+
+        private void SetTitleBar()
+        {
+            var coreTitleBar = CoreApplication.GetCurrentView().TitleBar;
+            coreTitleBar.ExtendViewIntoTitleBar = true;
+            Window.Current.SetTitleBar(AppTitleBar);
+        }
+
+        private void NavigationView_OnItemInvoked(NavigationView sender, NavigationViewItemInvokedEventArgs args)
+        {
+            // Getting the Tag from Content (args.InvokedItem is the content of NavigationViewItem)
+            var navItem = NavigationView.MenuItems
+                .OfType<NavigationViewItem>()
+                .First(i => args.InvokedItem.Equals(i.Content));
+
+            NavigationView_Navigate(navItem);
+        }
+
+        private void NavigationView_Navigate(NavigationViewItem navItem)
+        {
+            var item = _pages.First(p => p.Tag.Equals(navItem.Tag));
+            NavigationView.Header = navItem.Content;
+            ContentFrame.Navigate(item.Page);
+        }
+
+        private void NavigationView_OnLoaded(object sender, RoutedEventArgs e)
+        {
+            NavigationView_Navigate(Welcome);
+            NavigationView.IsBackEnabled = Frame.CanGoBack;
+        }
+
+        private void NavigationView_OnBackRequested(NavigationView sender, NavigationViewBackRequestedEventArgs args)
+        {
+            Frame.GoBack();
+        }
+    }
+}