Draft: Unbias PVs for charm HLT2 lines used in time-dependent measurements

Unbias the PVs for the charm HLT2 lines used to perform measurements of mixing and of time-dependent CP violation. Changes based on the examples in:

• https://indico.cern.ch/event/1395756/#5-persistency-changes-in-pvs
• https://indico.cern.ch/event/1395756/#6-pv-unbiasing-and-vertex-fitt

which are built based on the code here: https://gitlab.cern.ch/lhcb/Rec/-/blob/master/Tr/PatPV/src/ParticleUnbiasedPVAdder.cpp