Drive testing interface and cmd line tool

This PR introduces an interface and a command line utility for drive testing. In contrast to existing tools, like the "pwm" command, the user (or the GUI) is not required to care about the electrical interface the drive is connected to.

Driver support is planned at least for UAVCAN and PWM.

This PR is a rework of https://github.com/PX4/Firmware/pull/1275