Add binary info for named configuration settings

[kilograham]

this could be integers, booleans and possible pre-sized strings.

picotool could be used to read or set these values in an ELF, BIN, or UF2 (or on the device)... basically allows you to customize some settings in a pre-built binary

[lurch]

A bit like a trimmed-down version of https://www.raspberrypi.com/documentation/computers/raspberry-pi.html#raspberry-pi-4-bootloader-configuration ?