Reorganize project structure.

Marechai.App/Presentation/Views/Shell.xaml.cs

@@ -0,0 +1,14 @@
+using Microsoft.UI.Xaml.Controls;
+using Uno.Extensions.Hosting;
+
+namespace Marechai.App.Presentation;
+
+public sealed partial class Shell : UserControl, IContentControlProvider
+{
+    public Shell()
+    {
+        this.InitializeComponent();
+    }
+
+    public ContentControl ContentControl => Splash;
+}