[FEATURE REQUEST] Lightmap resolution compile option

[Pacman1105]

I think it'd be really great if there was an option to change lightmap resolution (and make texture size not break it)

This'd help with making better looking lighting (especially if it's behind a small grate texture)

example of Xash3d's higher light res compile option

example of a effect that could be improved with better lighting

same effect but with 4x resolution (I think, might've did the command wrong on compile)