Harmonize system status API and reporting

[sequoia-hope]

There are two main "Status" concepts in the Flutter system.

One is the status of the CC1200 radio chip, defined by the manufacturer and available via SPI (status is also attached to most communications pushed to the radio).

The other status is the "Flutter system state" or "Flutter network state", and is pretty much up to us as developers to define. I have started a plan for this, and it lives in a PDF and XML file (editable at draw.io) that attempts to define how Flutter should work, with notes about which conditions result in which "Status".

It would be very nice to come up with a unified plan for how to establish state and handle it for both the radio and the general Flutter system (which will at times need to know the radio state).