feature: UI: LDN Games Viewer

This window can be accessed via "Help" menu in the title bar.
This menu's data is synced with the in-app-list LDN game data, and that has been modified to hide unjoinable games (in-progress and/or private (needing a passphrase)). You can still see these games in the list.

src/Ryujinx/UI/ViewModels/Input/InputViewModel.cs

@@ -1,7 +1,6 @@
 using Avalonia.Collections;
 using Avalonia.Controls;
 using Avalonia.Svg.Skia;
-using Avalonia.Threading;
 using CommunityToolkit.Mvvm.ComponentModel;
 using Gommon;
 using Ryujinx.Ava.Common.Locale;