ps2x2pico Version 2.0

This is version 2.0 running all devices in report mode and compiled with Pico-SDK 1.5.1.
This should fix #35, #50, #59 and #61, please test multiple different mice.
Also #40 became active again since all devices now run in report mode and NKRO is implemented (for USB keyboards that support NKRO).

ps2x2pico.uf2 uses the mouse rate set by the host PC
ps2x2pico-100hz.uf2 uses fixed 100 Hz mouse rate, ignores host request
ps2x2pico-200hz.uf2 uses fixed 200 Hz mouse rate, ignores host request