Trajectory truth handling

[dguff]

Implement an option to avoid storing the full particle trajectories in the simulation output and store only the hits in the LAr volume instead.

[dguff]

In view of simulating high energy events (e.g., cosmic rays), we might want to store only trajectory points for particles produced with initial energy above a certain threshold

[dguff]

Global redesign needed. Avoid issues caused by filling the stack with secondaries (almost all of which are optical photons) waiting the program to track them. We can attach directly the SLArEventTrajectory to the track user information object.

[dguff]

Done in 6018567c4d7a1b3bf2ce020ed4b7c6d18b1d5b04