When moving to UEFI and secure-boot it's better to just reboot the system
for Machine Owner Key installation, then powercycling the machine.

This commit will use `reboot now` over `poweroff` after base system installation
and boot into installed image for smoketest handling.

This code path was unused during CI runs.

…faults

To use VNC you could run "make test -- --vnc"

…e disks

This is required to support proper disk ejection and not reloading the disk on
system reboot when operation in BIOS mode.

In the past the CLI based smoketest was always executed under an else branch in
the testcase if-statement. Instead of using negative logic move all testcases
to positive logic adding an empty "catch all" else path.

This adds support for UEFI Secure Boot. It adds the missing pieces to the Linux
Kernel and enforces module signing. This results in an additional security
layer where untrusted (unsigned) Kernel modules can no longer be loaded into
the live system.

NOTE: This commit will not work unless signing keys are present. Arbitrary
keys can be generated using instructions found in:

  data/live-build-config/includes.chroot/var/lib/shim-signed/mok/README.md

Rise upper limit for UID when working in an Active Direcotry integrated
environment. This solves the warning: vyos_bld's uid 1632000007 outside of the
UID_MIN 1000 and UID_MAX 60000 range.