commander generic setpoints for manual flight

[knmcguire]

Let's add some generic commander setpoints that is meant for manual flight, for both absolute roll/pitch and rate control.

The current way of how it is implemented in the Crazyflie is not ideal, since the response of rpyt setpoint can be changed by parameters which is a bit legacy. We don't want to remove that as that might break functionalities, but just an alternative way of sending rpyt setpoints that is more compatible with the other setpoints for velocity, hover position etc.

I would propose the following:

send_setpoint_manual = thrust percentage, roll/pitch abs attitude, yaw attitude rate
send_setpoint_manual_rate = thrust percentage, roll/pitch/yaw rate attitude