Move memtest86+ to `/boot/memtest86+/` on ISO 9660. That directory is
not copied to netboot artifact output.
Netboot boot menu https://ipxe.archlinux.org/releng/netboot/archlinux.ipxe
does not have entries for memtest and archiso-manager removes these files
(not the EFI one, though) before uploading the release files anyway.
There are claims that some UEFI allegedly natively support NTFS.
Preload the required GRUB modules to support booting from NTFS on such
systems.
Additionally preload the exFAT and UEF modules, because, why not?
Search for `/.disk/%UUID_SEARCH_FILENAME%.uuid` and pass the UUID of the
volume it's on as `archisodevice`. mkarchiso will replace
`%UUID_SEARCH_FILENAME%` with a hardcoded value generated using
`SOURCE_DATE_EPOCH` durring ISO build.
This allows to prepare an UEFI bootable installation medium by simply
copying the directory structure without having to touch `grub.cfg`.
Relying on the volume UUID instead of its LABEL also avoids collisions
of multiple ISOs created in the same month.
Fixes#202
