fix(build_library/legacy_bootloader): add menu.lst entries

these entries are needed for pvgrub, pygrub. Add them!
feat(image_to_vm): setup grub/menu.lst for xen

xen requires a /boot/grub/menu.lst for pygrub and pvgrub on partition 1.
Put it on the stateful partition for now and come back around and fix
this up when we redo the partition layout.