Add track position and momentum functors and change CLOSESTTOBEAM functor to be used in composition

This MR:

• Changes the behaviour of CLOSESTTOBEAM functor to be used in composition. Closes #432 (closed)
• Add 9 new functors: TRACK_POSVEC_CLOSESTTOBEAM (and its three components) and TRACK_MOMVEC_CLOSESTTOBEAM (and it's three components) and TRACK_PT.

Test with: Moore!1908 (merged) and DaVinci!793 (merged)

FYI: @mstahl and @sstahl