Can't distinguish analog pins that are for offline only use (Wifi conflict) - Want to use in offline mode

[tyeth]

We can offer all unused pins in offline mode, specifically all the analog pins.
Previously to now, they have had some missing from the interface due to wifi conflicts with one of the two onboard ADCs in ESP32 based boards.
In offline mode that doesn't matter, so we should include the pins in the definitions, but maybe with an extra property/flag for offline mode, or to stop io-rails (main website) providing them in the interface. Alternatively we could just add them anyway and provide a small indication of their extra limitations with an asterisk - then explained in the board guides wippersnapper analog page)

[tyeth]

Relates to Analog Pins should also be available as Digital Pins (assuming not input-only) #123