This also removes the need to pin share because we don't use the
status LED while user code is running.
The status flashes fallback to the HW_STATUS LED if no RGB LED is
present. Each status has a unique blink pattern as well.
One caveat is the REPL state. In order to not pin share, we set the
RGB color once. PWM and single color will be shutoff immediately but
DotStars and NeoPixels will hold the color until the user overrides
it.
Fixes#4133
This started while adding USB MIDI support (and descriptor support is
in this change.) When seeing that I'd have to implement the MIDI class
logic twice, once for atmel-samd and once for nrf, I decided to refactor
the USB stack so its shared across ports. This has led to a number of
changes that remove items from the ports folder and move them into
supervisor.
Furthermore, we had external SPI flash support for nrf pending so I
factored out the connection between the usb stack and the flash API as
well. This PR also includes the QSPI support for nRF.
