Package nexmon: broadcom firmware patches to fix broadpwn and enable monitor mode

As mentioned in #513 (closed).

Repository is here.

Build instructions are only for Ubuntu/Raspberry Pi, and appear to require some 32-bit libraries that Alpine does not package.

I can think of three options, none of which are particularly fun:

1. Package and maintain the required 32-bit libraries.
2. Build firmware binaries and package them as blobs. (Not ideal for transparency.)
3. Create ubuntu buildroot with docker and build them that way? ;) Just kidding, probably.

There's also the question of, if successfully packaged, do we ship all firmwares as one package, or split it into, e.g. nexmon_bcm4339, etc.? It seems like each chipset also has multiple patch sets -- bcm4339 has an anti_broadpwn patchset and the main nexmon patch.

Does anyone have any other ideas on how to package them?

EDIT: Also, as @ollieparanoid mentioned, we definitely have to disable statistics collection when building.