Option to easily switch between different excitation trajectories

[nepfaff]

Different works propose to use different joint trajectories. We want to easily try different methods by changing a config parameter.

Start by allowing to switch between Andy's trajectories and the trajectories from "Fast Object Inertial Parameter Identification for Collaborative Robots".

[nepfaff]

Blocked by https://github.com/nepfaff/robot_payload_id/issues/13