And to flesh out, this requires two main pieces:
1) Copying over a grub.efi and creating a grub.conf.  This is going into
livecd-creator
2) Some livecd-iso-to-disk tooling so that it doesn't try to do syslinux if you
ask it for a mactel image.  Note that for a mactel image, chances are you won't
be able to create the image non-destructively as we need a GPT label.  But such is
life

For the "future" case, this should be able to be clean.  Once I have the future
case working, I'll try to munge a variant of livecd-iso-to-disk.sh that can be
used with F9 images (although it'll likely require being run from an F9 box of
the appropriate arch)

And support for this built and tested.  Works with F9 kernel at least, something
seems bustificated with the rawhide kernel + EFI booting at the moment

Closing out bug that's been in MODIFIED for a while.