feat(targets): ✨ Add Raspberry Pi Pico W

[ZZ-Cat]

Overview

This Pull Request adds support for the Raspberry Pi Pico W

[ZZ-Cat]

Right-oh, @britannio.

Can you check out the ZZ-Cat/issue109 branch, flash one of the examples onto your Raspberry Pi Pico W and let me know if it's working for you?

If anything crops up, you may go into CFA_Config.hpp and turn on CRSF_DEBUG_ENABLED and CRSF_DEBUG_ENABLE_COMPATIBILITY_TABLE_OUTPUT, re-flash your target, screenshot the results in the Serial Monitor and post those screenshots here.

Aside from #108, by rights there should not be any other issues.

[britannio]

Thanks, I'll test it out tomorrow (was away for a few days).
I'm now using https://github.com/britannio/pico_crsf but it's fair that I ensure the feature I requested works.

[ZZ-Cat]

Yeha.

I plan on adding more RP2040 targets soon, because this is something that's requested a lot (it's a close second to ESP32 targets).
What caused me to hold off on it was an apparent falling out between PlatformIO and Raspberry Pi Trading; and about a year ago, there wasn't any way to add Earle Phillhower's Arduino-Pico to PlatformIO... until I found out very recently that it's been integrated.

It's a slightly similar situation with STM32 support as well. I want to add in STM32duino support either alongside what I already have or replace it entirely. As far as I am aware, there is yet to be PlatformIO integration for STM32duino.

I believe that the more targets CRSF for Arduino is compatible with, this increases the number of applications it can be used in, and people can pick whichever hardware fits their budgets and needs.