Volume Hotkeys (#3500)

* Initial GTK implementation

* Less messy and Avalonia imp

* Move clamping to HLE and streamline imps

* Make viewmodel update consistent

* Fix rebase and add an english locale.

Co-authored-by: Mary-nyan <mary@mary.zone>

Ryujinx.Common/Configuration/Hid/KeyboardHotkeys.cs

@@ -9,5 +9,7 @@
         public Key ToggleMute { get; set; }
         public Key ResScaleUp { get; set; }
         public Key ResScaleDown { get; set; }
+        public Key VolumeUp { get; set; }
+        public Key VolumeDown { get; set; }
     }
 }