generic trajectory support

[andreihaidu]

Abstract trajectory drawing representation, where the input should be an array of poses / 3d points.

[daniel86]

@andreihaidu thanks for the report!

1. robot trajectory queries are super slow because each sample is queried individually
2. it would be nice to have a first order entity Trajectory
3. it would be nice to align how unreal and robot pose data is used in knowrob