Post-processing used a static (outdated?) GRUB image for USB image generation, but it is better to use the GRUB image produced as part of the building process, which ensures that the actual compiled GRUB version is used as bootloader in our images and not an outdated one.
Post-processing previously embedded the 64-bit EFI bootloader to 32-bit builds, as no architecture checks were in place. This was changed to check for architecture and embed the correct EFI bootloader for the respective target architecture instead.
The GRUB configuration was changed to use a menu, to allow the user to choose between standard and nomodeset parameters, while also allowing the user to edit the command line to append other kernel parameters they may need for their systems.
The vanity kernel image name was returned to bzImage to clearly mark the image for what it is, and to remain consistent with the ISO file generation where we have no direct control over the image now.
Signed-off-by: desertwitch <24509509+desertwitch@users.noreply.github.com>
