Add in the PhotonValidator plots for E/Etrue vs Ntvx, sigmaE/E vs eta, et, NVtx, update plotting scripts and layout
Update PhotonValidato and TkConvValidator to be compliant with multithreading
Merge pull request #3134 from nancymarinelli/egmValidationMigrationToMultiThread

DQM -- Validation/RecoEgamma migration to multi thread