- update root=... variable correctly if zfs is used
- keep a copy of the initrd in /run/initramfs to allow systemd
  the jump back to the initrd. This is what a dracut initrd
  would do as well and it also allows operations after the root
  filesystem is umounted, e.g export the zfs pool
- fixed installBootLoader() to allow skipping the installation
  of the legacy bios grub2 loader if the system doesn't have the
  bios grub2 modules installed but EFI is selected as firmware