[Feature]: Tune Velocity Controller PID Parameters

[hellschwalex]

Description

With the new Acting Test Node the VelocityControllers PID-controller is now tunable.
Important for tuning:

• Drive at velocities close to the target velocity
• Driving at exactly max_velocity is not that important (small margin allowed)
• Full throttle range [0:1] should be used

Definition of Done

• Velocity PID-controller always drives at or closely around the target-velocity ( 2m/s maximum margin)

[hellschwalex]

Tried tuning PID-controller with Ziegler-Nichols method without any success.
Tried classic tuning of the PID-controller and reached a not-optimal but good working solution (see branch)

[hellschwalex]

This Issue is finished and may be closed with #135 being the follow-up Issue to be looked at.