feat: swap to negativo17 as nvidia driver source, again

[bsherman]

This reworks all the bits in akmods for nvidia:

• removes nvidia driver version as only latest is supported
• adds negativo17-fedora-nvidia repo to ublue-os-nvidia-addons RPM
• removes extra metadata from the nvidia-vars create in image

This PR will require a corresponding PR in hwe to ensure proper repos are being used and the new package names are installed since negativo17 has some different package naming.

This is a second attempt since the first was reverted: (see #172)