Nvidia script refactoring

[killeik]

So, in #1417, I discovered that some shenanigans are needed to enable hibernation for Nvidia users.
Somehow I found myself refactoring this script :D

1. Installs headers to all installed kernels.
2. Adds modules to a separate file /etc/mkinitcpio.conf.d/nvidia.conf instead of using sed on /etc/mkinitcpio.conf.
3. Uses limine-mkinitcpio instead of mkinitcpio -P (this removes another interactive confirmation).
4. Creates env = for nvidia in envs.conf instead of hyprland.conf.
5. Exits early, so all the script not indented
6. Overall improvements

I also added migration to standardize the configurations for already existing users.

@Kn0ax, as the author of the script, please let me know if you have any concerns.

[Kn0ax]

Hi,
Thanks for taking your time and trying to improve it.

I will have a few comments.

[Kn0ax]

i think its ready to merge :)
thanks <3