[WIP][Virtualization]: Add update_nvram for uefi autoyast installation

[alice-suse]

This PR aims to solve the problem in https://progress.opensuse.org/issues/166712#note-23, for which if a job with secure boot enabled is installed onto a disk, that is different from the disk that our virtualization jobs will install on(for both sles and sle micro), the installed virtualization host OS will not boot successfully.

Solution is to erase disks before real installation starts:

• for sles, add in autoyast pre-script the disk erasing script

• for sle micro, at ipxe_install, call prepare_disks

• Related ticket: https://progress.opensuse.org/issues/166712

• Verification run:

- kermit(uefi)
  - guided_btrfs secure boot test: https://openqa.suse.de/tests/15547054 (trigger the issue)
  - sles vt 12sp5 kvm host: https://openqa.suse.de/tests/15547055
  - guided_btrfs secure boot test: https://openqa.suse.de/tests/15547303# (trigger the issue)
  - sles vt 15sp6 xen host: https://openqa.suse.de/tests/15547634#(wip)

- scooter(uefi)
  - guided_btrfs secure boot test: https://openqa.suse.de/tests/15547066 (trigger the issue)
  - sles 15sp7 kvm host: https://openqa.suse.de/tests/15547061
  - guided_btrfs secure boot test
  - sle micro:  https://openqa.suse.de/tests/15519906#step/ipxe_install/63
  - post-fail hook verification: https://openqa.suse.de/tests/15547254#

- regression test on non-uefi machine
  - 15sp7 xen : worker amd-zen3-gpu-sut1,https://openqa.suse.de/tests/15547635#