An easier way to check if secureBoot is enabled is by running mokutil --sb-state
We have to do this way now because on systemd v258 `bootctl status` returns non 0 value if systemd-boot is not properly installed, which is to be expected when using Limine.
This patch adds a NixOS test for Limine on BIOS systems. It also fixes
some formatting in `nixos/lib/make-disk-image.nix`.
Signed-off-by: John Titor <50095635+JohnRTitor@users.noreply.github.com>
