misc: small Avalonia project restructure

Moved AppLibrary, Configuration, and PlayReport namespaces to Ryujinx.Systems, add the compat list stuff in the base Ryujinx.Systems namespace.
Moved the compatibility UI stuff to the proper UI view/viewmodel folders.

src/Ryujinx/Systems/AppLibrary/ApplicationCountUpdatedEventArgs.cs

@@ -0,0 +1,10 @@
+using System;
+
+namespace Ryujinx.Ava.Systems.AppLibrary
+{
+    public class ApplicationCountUpdatedEventArgs : EventArgs
+    {
+        public int NumAppsFound { get; set; }
+        public int NumAppsLoaded { get; set; }
+    }
+}