add reboot to BIOS to vendor menu

[adghayes]

Overview

Adds a reboot to BIOS option to the vendor menu. Tested in my VM. Using the same command we currently use in vxsuite to do the reboot.

Before

After

[adghayes]

@arsalansufi I think we should rename the whole vx-admin user and config files to use the word vendor, but since the script are referenced I didn't want to dig in too much right now and make a mistake that'll hold up the next build, but I certainly can (it's probably safe, just find and replace)

[arsalansufi]

LGTM!

[arsalansufi]

Discussed with @adghayes in person and agree with the decision to rename vx-admin vx-vendor! The user is only used to access the basic configuration wizard and the vendor menu, both vendor-specific.

And it'd be nice to better disambiguate VxAdmin the machine from vx-admin the system user

[arsalansufi]

Ticketed: votingworks/vxsuite#5509