cleanup ele/photons

[mariadalfonso]

1. some variable stored might be obsolete
   http://dalfonso.web.cern.ch/dalfonso/XPOG/NANV8/Summer20UL18NanoAODv2_TTToSemiLeptonic_size_report.html#Electron

• remove Electron_cutBased_Fall17_V1 are not recommended for Run2
• check who's is using electron_jetRelIso, Electron_jetPtRelv2 are being used for

2. ALL ph/ele are used
   https://github.com/cms-sw/cmssw/blob/master/PhysicsTools/NanoAOD/python/photons_cff.py#L170-L172
   https://github.com/cms-sw/cmssw/blob/master/PhysicsTools/NanoAOD/python/electrons_cff.py#L310-L312

• check increase pt: i.e. 10/15 GeV are not used, (BPH used lowPTele from mini)
• evaluate adding selection i.e. OR of [ID + fakable ID ] can be different per

3. Some variable might not be needed (see nanov9)
   https://cms-nanoaod-integration.web.cern.ch/integration/cms-swmaster/mc106Xul17v2_size_report.html#Photon

• Electron_mass 2.3% (similar occupancy as the pt)
• Photon_mass 3.1% (similar impact of the pt) some non initialised value
  see http://dalfonso.web.cern.ch/dalfonso/NANO/massDump.txt
• Photon_mvaID_Fall17V1p1 is needed ? Photon_mvaID is already there and correspond to the Fall17V2
• Electron_dr03TkSumPt is used in the reco chain in PF Egamma Filter (electron ID), but
  Swagata is not sure why it is needed in nano, or if any analysis team is using it or not.

4. improve self documentation

• Hgg photons variables in nanoAODs cms-sw/cmssw#36526 (comment)
• there is a bug in the Photon_vidNestedWPBitmap https://cms-nanoaod-integration.web.cern.ch/integration/cms-swmaster/mc106Xul17v2_doc.html#Photon (you can see the PhoGenericRhoPtScaledCut shows up 3 times)

[mariadalfonso]

'remove Electron_cutBased_Fall17_V1 are not recommended for Run2' done in cms-sw/33701

[mariadalfonso]

I close this as a lot of slimming/clearing/renaming was done.
Still the configurations could be simplified.