Moved application code to the Application layer

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

ModernKeePass10/Converters/BooleanToVisibilityConverter.cs

@@ -0,0 +1,29 @@
+using System;
+using Windows.UI.Xaml;
+using Windows.UI.Xaml.Data;
+
+namespace ModernKeePass.Converters
+{
+    [Obsolete]
+    public class BooleanToVisibilityConverter : IValueConverter
+    {
+        public object Convert(object value, Type targetType, object parameter, string language)
+        {
+            var boolean = value as bool? ?? false;
+            return boolean ? Visibility.Visible : Visibility.Collapsed;
+        }
+
+        // No need to implement this
+        public object ConvertBack(object value, Type targetType, object parameter, string language)
+        {
+            var visibility = value as Visibility? ?? Visibility.Visible;
+            switch (visibility)
+            {
+                case Visibility.Visible: return true;
+                case Visibility.Collapsed: return false;
+                default:
+                    throw new ArgumentOutOfRangeException(nameof(value));
+            }
+        }
+    }
+}