CMS - script for the pile-up record

[katilp]

for cernopendata/opendata.cern.ch#3569

Write a script to get the pile-up record json.

Single production step (process neutrino particle gun = nothing) see McM
Sampling pileup from the GEN-SIM pile-up sample
/MinBias_TuneCP5_13TeV-pythia8/RunIISummer20UL16SIM-106X_mcRun2_asymptotic_v13-v2/GEN-SIM

Can use parts of the sim scripts.

[katilp]

The min-bias GEN-SIM sample does not show in the provenance query because it is not a parent dataset.
The current mcm_store.py requires an update for the pileup name search DIGIPremix -> Premix

In any case, a separate step is needed to show the generator parameters for GEN_SIM.