ports/rp2/boards: Add SparkFun Thing Plus RP2350

[sfe-SparkFro]

Summary

To add support for this board from us: https://www.sparkfun.com/products/25134

Depends on #16057

Also depends on #15620, but this can be merged before that if needed

Testing

Tested with above dependencies merged locally on an initial production board, and all seems well.

[github-actions]

Code size report:

   bare-arm:    +0 +0.000% 
minimal x86:    +0 +0.000% 
   unix x64:    +0 +0.000% standard
      stm32:    +0 +0.000% PYBV10
     mimxrt:    +0 +0.000% TEENSY40
        rp2:    +0 +0.000% RPI_PICO_W
       samd:    +0 +0.000% ADAFRUIT_ITSYBITSY_M4_EXPRESS
  qemu rv32:    +0 +0.000% VIRT_RV32

[sfe-SparkFro]

Also added image: micropython/micropython-media#76

[dpgeorge]

This is blocked on #16057.

[sfe-SparkFro]

@dpgeorge No longer depends on #16057! I realized this was using an old implementation, so updated to match the Pico 2 W implementation. Still have the soft dependency on #15620, but that doesn't need to prevent this from being merged.

[dpgeorge]

Rebased, squashed and merged in 0a9cc90