Adding an option for transparent scoreboard and keystrokes

[graceful kernel]

currently, when you want to make either of these 2 transparent, you have to turn down the opacity of the background colour, and i feel like that could confuse some people.

[graceful kernel]

also considering that theres an option to make the chat transparent, so it would make sense having that option for every mod that has a background that isn't removable

[ember nebula]

you can make the background transparent (for both scoreboard and keystrokes)

[lyric heath]

Already a feature

[slate nest]

all of this is already in lc

[graceful kernel]

only for some mods though

[slate nest]

but for scorebaord, keystrokes and chat it is at least

[granite coyote]

Opacity slider?