Coreboot configuration

## Problem

Requested by @Sean-StarLabs

## Proposal

>One thing I'd really like to do, so every base is covered, is put some way of changing coreboot settings into switchboard, maybe next to the fwupd integration.
>
>This was my "5-minute" approach:
https://github.com/StarLabsLtd/coreboot-configurator
>
>Technically, it's a relatively easy job, and it could be written in bash in a minute or so, to work with any coreboot setup. Something like:
>> Check if /sys/devices/virtual/dmi/id/bios_vendor == "coreboot"
>> Get possible settings with nvramtool -a
> For each setting, get the possible options with nvramtool -e $setting
>> Give these options to the use, if they change, write them with nvramtool -w $setting=$option

## Prior Art

We have firmware updates here, and this feels at least tangential.