Add option to change controller LED color (#572)

This allows the user to change the controller LED while using Ryujinx.
Useful for PS4 and PS5 controllers as an example.

You can also use a spectrum-cycling Rainbow color option, or turn the LED off for DualSense controllers.

---------

Co-authored-by: Evan Husted <greem@greemdev.net>

src/Ryujinx/Input/AvaloniaKeyboardDriver.cs

@@ -59,6 +59,8 @@ namespace Ryujinx.Ava.Input
             return new AvaloniaKeyboard(this, _keyboardIdentifers[0], LocaleManager.Instance[LocaleKeys.AllKeyboards]);
         }
 
+        public IEnumerable<IGamepad> GetGamepads() => [GetGamepad("0")];
+
         protected virtual void Dispose(bool disposing)
         {
             if (disposing)