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
The RP2040 is new microcontroller from Raspberry Pi that features
two Cortex M0s and eight PIO state machines that are good for
crunching lots of data. It has 264k RAM and a built in UF2
bootloader too.
Datasheet: https://pico.raspberrypi.org/files/rp2040_datasheet.pdf
