- install ovmf for the firmware
- set uefi in the vars (currently always on, we need a second test
  for bios)
- main.pm now always asserts the install bootloader for install tests
- installer test no longer assert bootloader
- new bootloader-uefi needle (matches bootloader tag)
- new bootloader test looking for bootloader needle and either starting
  grub or letting isolinux do its autostart thing
- adjust installer tests to let system settle down again before starting
  the installers themselves
-