store PileupJetIdentifier in flashgg::Jet, accessors for relevant, 0 for...

... others.

We are now using cut-based PU jet ID (as per Legacy analysis).  Old code based on accessing PU Jet ID MVA will no longer work, and flashgg::Jet no longer stores mva.  In all TagProducers, the flashgg::Jet::passesPuJetId method is now used, which takes a diphoton as vertex as an argument.  (betaStar and RMS are also accessible via methods taking the same arguments.)

The entire PileupJetIdentifier object is stored for each vertex.  However, most variables are set to 0, and I understand this will greatly reduce disk usage due to CMSSW's zero-supression.  In the course of future development, different pileup jet ID configurations could be used and additional variables could be stored and given accessors, with minimal changes to the internal structure of flashgg::Jet or the JetProducer.