Idea: add support for ch55x family

[stripu]

Hello!
Thank you for your work on this library, as it's one of the best for low memory devices, like the attiny family.
Lately I've been experimenting with the ch55x family of microcontrollers and they're pretty capable low cost devices that are usb oriented.
Unfortunately there's no RF capability developed for the arduino port yet (https://github.com/DeqingSun/ch55xduino) so I was wondering how hard it might be to add support to your library for these devices.
I'm not really capable of doing such a task, so here's hoping that I sparked your interest in checking this idea out :)

Best regards