New Feature: Ability to switch keyboard action buttons

[osioke]

Description

Currently only pressing the Enter or Return key and the Spacebar key change a action key in the settings, it isn't clear how to change a key, especially as one keyboard seems to control both players (not sure if this action is intended even).

Alternatives & Prior Art

Maybe the Enter key is set as a non-action key and tapping it on the action keys in the setting allows one tap another key after to change said action key.