CAN address enumeration

[napowderly]

Goal: super quickly enumerate devices, ideally without flashing new FW or requiring PC connection.

Imagining with button + LEDs, the user could toggle between colors representing different addresses. The state should be saved in non-volatile memory, so the address is preserved after power cycling.

This would be useful for applications where the user writes controller code on an RPI or Arduino and wants an easy way to reference the motors.