Match board names more closely to CircuitPython

[dhalbert]

Some of the board names don't match the board names for CircuitPython, which has caused minor support issues. It would be nice to match them up as much as possible. In some cases, though, (like non-Express Feather M0 boards), there is a single bootloader but multiple CPy builds.

Also the arcade_* boards could be renamed to *_arcade to make them easier to find alphabetically.