Implemented automatic maneuvers, 2-way safety, pilot and PC override, engine control during maneuver

This reverts commit 0c81a19decde6ddfe4ce87c34c762ea15fd3ab09.

But fix the two crucial problems:
- When to begin the ramp?
There's a calculation now for the velocity ramp initial value
such that the resulting thrust is zero at the beginning.
- When to end the ramp?
The ramp is applied to the upwards velocity constraint and it
just ramps from the initial value to the velocity constraint
which is applied during flight. Slower/going down is always possible.

Without always updating the takeoff state it will not get skipped when
the takeoff happened manually and when you switch from manual to position
mode the drone goes to idle and falls.

There are two local_position_setpoint in the position controller.
One describing the setpoint the task gives to the position controller
and a second one with the output of the position controller. I corrected
the wrong one during takeoff because the new takeoff thrust ramp runs after
the controller and not before.