Moved application code to the Application layer

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

ModernKeePass/Common/ResourceHelper.cs

@@ -0,0 +1,16 @@
+using Windows.ApplicationModel.Resources;
+
+namespace ModernKeePass.Common
+{
+    public class ResourceHelper
+    {
+        private const string ResourceFileName = "CodeBehind";
+        private readonly ResourceLoader _resourceLoader = ResourceLoader.GetForCurrentView();
+
+        public string GetResourceValue(string key)
+        {
+            var resource = _resourceLoader.GetString($"/{ResourceFileName}/{key}");
+            return resource;
+        }
+    }
+}