xcp-ng bios mostly working, grub almost working
Changes:
- bootx64.efi to grubx64.efi in Loader section
- add custom grub template for multiboot2
- fix boot paths for xen bios boot and swap kernel parameter to mboot.c32
Notes:
- works when you extract xcp-ng iso, replace mboot.c32 using syslinux 6.03 mboot.c32 in bios dir from source, tar files, then upload to drp (and remove hash)
- grub boot works when commands are manually entered, but bundled grubx64.efi looks for grub.cfg at (tftp)/EFI/xenserver/grub.cfg (does not request MAC or GUID based files)