added feather mo wifi

[MyloniteMaine]

added support

[tyeth]

Hey @MyloniteMaine thanks for contributing!

This looks mostly great, cleanup the blank lines in the json, and link to the correct product learn guide (scroll to end of product page - select 2nd variant - to find the relevant learn guides https://learn.adafruit.com/adafruit-feather-m0-wifi-atwinc1500 ).
The pinout might be missing a few pin definitions, I feel it's better to add more that may not work and remove them again later if needed after testing them all, as they may not work for certain purposes or conflict (I haven't looked properly yet but D0/D1 at least made me want to comment).

If you want to try building the firmware (support will need adding) and pretending to be another board id, then you can at least get past the compile stage and watch the serial monitor and see if wifi then mqtt connects, then it will fail to register device, or may register but all the pin info it receives will be wrong until this is merged. We'll have a look next week, hopefully my colleague @brentru has one to hand, unfortunately I haven't got this board (I can order one).