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/AppHost.cs

@@ -587,6 +587,11 @@ namespace Ryujinx.Ava
                 return;
             }
 
+            foreach (IGamepad gamepad in RyujinxApp.MainWindow.InputManager.GamepadDriver.GetGamepads())
+            {
+                gamepad?.ClearLed();
+            }
+
             _isStopped = true;
             Stop();
         }