Notes on how to use freebsd-wifi-build to build an image for the Onion Omega2+

freebsd-wifi-build: https://github.com/freebsd/freebsd-wifi-build

Onion Omega2+: https://onion.io/omega2/

These notes are largely insipred by github user sysadminmike's notes: https://github.com/sysadminmike/freebsd-onion-omega2-build

These notes are also based on (unpublished) notes from Jakob Alvermark