[Feature Request] Sticky keys

[LiskoFINAL]

Hi, after an accident I got some problems with my hands and thanks to this I can still play games that otherwise I wouldn't be able to. Thank you very much for this. I still have some problems in certain games that makes them inaccessible to me. What would help me a lot it's a way to keep buttons pressed by only "toggling" them until they are pressed again or when another configurable one is pressed. I put a configuration example to explain this better:

{"keys":[{"press":"R","get":"R","heldUntil":"A,R"}]}

So when I press R it's keep pressed until I press R again or if I press A. I hope I explained it good enough that someone would help me so that I could play a lot of games that now I can't. Thanks to you for this amazing project that helps me a lot, keep up and I hope a day this feature will also be in.