Add the LowPtPLV calculation/decoration & migration to unique_pointer for AnalysisCommon/LeptonTaggers package
Given that the PLV isolation WPs (which uses the LowPt tune for pT<12GeV) have been officially supported by the CP now, it has been decided to compute the LowPtPLV score in the derivation making stage together with the nominal PLV scores. This also aims to reduce the derivation size (i.e. currently one needs to write out all the PLV input variables to compute the LowPtPLV score at the analysis level) as well as avoid dependency of future derivation content change. Also as suggested earlier, the pointers used in the code are changed to unique pointers.
Test has been done by running on a ttbar AOD file into DAOD_SUSY2.
The variables are written out as intended, and the LowPtPLV score values are confirmed to agree with those calculated in CP::IsolationSelectionTool.
More tests are ongoing with the other MCs and data.
[EDIT] Validation done with more MC (one file from Zee/Zmumu/diboson) and MC as well, and all the output makes sense.
(In turn, a bug in CP::IsolationLowPtPLVTool::augment is found; it seems to compute the BDT score for leptons without the associated track jet found, while they should be thrown away with assigning the BDT score=-1.1.).
This MR should be ready to go.