Added RP2040 ( Pico W ) Support

ElegantOTA ( and Pro ) now officially supports platforms other than ESP family! 🎉 I think it's a good move towards making it the-facto library for all wireless MCUs. Really excited about the future of ElegantOTA!

Changelog:

• Added RP2040 ( Pico W ) Support
• Added setAutoReboot ( @mathieucarbou )
• Improved auth logic ( @mathieucarbou )
• Improved DEBUG defs ( @mathieucarbou )
• Switched to std::functional for callbacks ( allows lib to be used in classes ) ( @mathieucarbou )
• Added note in Async Demo for enabling async mode
• Minor bug fixes and improvements