Add Sparkfun Thing Plus Matter - MGM240P support

[ruddycanuck]

• Feature Request.
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Configuration

Operating system: Windows 10

PlatformIO Version (platformio --version): PlatformIO Core, version 6.1.13

Description of problem

Arduino, Sparkfun and Silicon Labs have a new Matter project: https://github.com/SiliconLabs/arduino/tree/main/libraries/Matter

I would like to use VS Code to program the Sparkfun Things Plus Matter ( Model DEV-20270 ) dev board using the Silicon Labs developed Arduino Libraries. (Arduino compiling is painfully slow.)
https://www.sparkfun.com/products/20270

I cannot find this board in the Platformio device list.

Steps to Reproduce

1. In VS Code - Platformio select 'Import Arduino Project'
2. Attempt to find the Sparkfun Thing Plus Matter - MGM240P

Actual Results

Product is not listed.

Expected Results

Product listed and Platformio able to use the Matter libraries from Arduino

Additional info

This board is available in Arduino - board info is from https://siliconlabs.github.io/arduino/package_arduinosilabs_index.json
The board comes with all of the appropriate Matter Arduino libraries for this Sparkfun and the Silicon Labs xG24 Explorer Kit dev boards.

[LorbusChris]

This is the same family of MCUs that is going to be used in the upcoming Arduino Nano Matter (which uses the MGM240S) and which'll also be supported in https://github.com/SiliconLabs/arduino

[MitchTalmadge]

More info about Arduino Nano Matter using MGM240SD22VNA:

• https://store.arduino.cc/pages/nano-matter
• https://docs.arduino.cc/hardware/nano-matter/

[LorbusChris]

This draft PR might be a good starting point for anyone looking to add support for the Sparkfun Thing Plus Matter and Arduino Nano Matter boards and the Silabs Arduino core:

platformio/platform-siliconlabsefm32#8