Feature Request: Add board support for Adafruit Feather RP2040

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Configuration

Operating system: All (W10, Linux, MAC)

PlatformIO Version (platformio --version): Core 6.1.5, Home 3.4.3

Additional info

Using C/C++, Arduino, with VSCode and 'Black Magic Probe'

No file, test, or entry point is named in the issue. Start by identifying how this repository defines supported Raspberry Pi boards and compare the existing RP2040 board support; done means the Adafruit Feather RP2040 is recognized and can build and upload with the stated C/C++, Arduino, VSCode setup.