Add class TrajectoryRef and use it in TrajectoryPosition and FollowTrajectoryAction
Describe the feature
TrajectoryRef should be created according to RouteRef with either a inline trajectory definition or a catalog reference to an existing trajectory.
Also TrajectoryRef can be used in FollowTrajectoryAction: Make trajectory and catalogReference deprecated and introduce trajectoryRef
Describe the backwards compatibility
Backward compatible using deprecation.
Additional context
This solves: 243