Porting a set of B2OC lines to the ThOr framework.

This MR is a prototype to port HLT2 B2OC lines to the ThOr framework (Functors + Combiners).

NB: the new lines are not yet tested (except for building a functor cache for them) cause the ThOr/LoKi comparison is not there yet (large disagreements). A comparison test will be added once that's in better shape. That should arrive during the hackathon.

The ported lines are:

• Hlt2B2OC_BdToDsmPi_DsmToHHH_Line
• Hlt2B2OC_BdToD0PiPi_D0ToHH_Line

A set of D lines were also added (for now) for testing purposes.

Depends on:

• Rec!2283 (merged), for BPVLTIME implementation
• Phys!868 (merged), for new ThOr combiners
• LHCb!2910 (merged) for new MatVec operations

cc: @apearce, @mvesteri, @nnolte

Next steps are the implementation of:

B2OC Hlt2 lines:

• Hlt2B2OC_BdToDsmK_DsmToHHH_BDTGtm1d0_Line
• Hlt2B2OC_BdToDsstmK_DsstmToDsmGamma_DsmToHHH_Line
• Hlt2B2OC_BuToDst0Pi_Dst0ToD0Pi0Resolved_D0ToKsLLHH_Line Filter to implement:
• ParticleFilterWithTMVA

ThOr functors equivalent to LoKi ones used in B2OC lines:

• CL
• BPVLTIME
• HASTRACK
• MIN/MAX/INTREE
• AHASCHILD