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.Ava/Common/KeyboardHotkeyState.cs

@@ -9,6 +9,8 @@
         Pause,
         ToggleMute,
         ResScaleUp,
-        ResScaleDown
+        ResScaleDown,
+        VolumeUp,
+        VolumeDown
     }
 }