Removes:
* AUTORESET_DELAY_MS which never did anything but was introduced
somehow.
* CIRCUITPY_BOOT_BUTTON in all but one ESP board because they all have
them. There is a default based on the strapping pins.
* BOARD_USER_SAFE_MODE_ACTION because it was all the same for boards
with boot buttons. Now the safe mode code manages the message.
This allows you to list and explore connected USB devices. It
only stubs out the methods to communicate to endpoints. That will
come in a follow up once TinyUSB has it. (It's in progress.)
Related to #5986
Dan Halbert
Scott Shawcroft
Bruce Segal