[feature request] Custom launch command line options.

[Weroxig]

I need prime-run to fix this:

Switching to resolution 2560x1440 failed, trying lower one
Switching to resolution 2560x1440 failed, trying lower one
All resolution switches have failed
Screen: DX11 could not switch resolution (2560x1440 fs=1 hz=0)

so currently, I have to run the launcher itself with prime-run so that the game runs with the desired gpu