Support usb with cherryusb

[sakumisu]

Dear raspberrypi friends,

I have ported rp2040 usb ip with cherryusb, and provide all the device class demos, see rp2040 device demo, and host driver and demo is on going.

But i do not know if i have the chance to pr cherryusb lib in pico-sdk, can someone review and tell me? If no , i will add the custom cmake script in my repo. Thank you!