Add option to toggle top or bottom backlight

[cooolgamer]

I'll test it later and merge if it works, I looked at the code rq and it looks alright. I just have a request, it would be to swap bottom with top, like, the option in extra config would be enabled to toggle TOP screen, and disabled to toggle BOTTOM screen

[exalented]

[I would like] the option in extra config .. to toggle TOP screen, and disabled to toggle BOTTOM screen

Done

[cooolgamer]

looks good 👍