Remove triggerhappy and charging-sdl

It doesn't seem like anyone is interested in putting in the effort to fix charging-sdl, and triggerhappy isn't used by anything else in pmOS. There are also apparently issues with triggerhappy's packaging: #1929 (closed)

Given that triggerhappy's upstream is dead, and we have hkdm as a replacement, I think we should remove it. Similarly, since it doesn't seem like anyone is interested in fixing charging-sdl, let's remove it too.

With that said, I could be sympathetic to keeping triggerhappy around given that end users seem to find usecases for it and they may not want to switch to hkdm for one reason or another. I'd like to hear your opinions about this.