Created the Avalonia MVVM template, split the CLI into Avalonia.UI and Avalonia.Core

AutumnLauncher.Core/Startup.cs

@@ -0,0 +1,11 @@
+namespace AutumnLauncher;
+
+public class Startup
+{
+    public void AppStart()
+    {
+        Directory.CreateDirectory(Configuration.DataDir);
+        Directory.CreateDirectory(Configuration.ConfigDir);
+        SqliteData.CreateDatabase();
+    }
+}