reference_hardware: Document ARM64 Raspberry Pi CM4 CANOPi board setup

Task https://phabricator.apertis.org/T8966

The Eclipse KUKSA CANOPi [0] is a baseboard for the Raspberry Compute Module 4 [1].

[0] https://github.com/boschresearch/kuksa.hardware)

[1] https://www.raspberrypi.com/products/compute-module-4/

Signed-off-by: Ariel D'Alessandro ariel.dalessandro@collabora.com