Fixes #2262 and GFX rewrite

[svartkanin]

This fixes #2262 and rewrites the GFX installation logic to something (hopefully) simpler

[Torxed]

Won't this make it so nvidia package is not installed? Which is needed for some platforms? Or we rely solely on the -dkms and add the nvidia hooks to build the driver each kernel upgrade?

[svartkanin]

Maybe I missed something but in the old code Nvidia didn't seem to be installed at all. But please double check that I didn't miss anything

I've actually tried installing nvidia and nvidia-dkms which threw a conflict error

[Torxed]

This could solve:

• Missing Nvidia Proprietary Driver after archinstall Script with August Arch Linux ISO's  #2002
• Add nvidia-drm.modeset #2214 (slightly related)

So installing nvidia-dkms instead of nvidia should work, the downside being that every upgrade will be slower as the kernel modules needs to be compiled during installation (this is done automatically AFAIK).

I'll merge this for now, but we should work on a fix to:

• Install nvidia if only linux kernel is selected (And also install linux-headers)
• Install nvidia-lts if only linux-lts kernel is selected (Also linux-lts-headers)
• Install nvidia-dkms if combintions of the above or none of the above was selected

That is the supported packaging from the package maintainers. But -dkms should work on all of the above - just slower upgrades.