Prefiring maps

See TWiki and personal homepage by Laurent Thomas. Two versions exist:

• A version with the correction factors integrated over the year for 2016 and for 2017 separately, with finer binning: L1prefiring_jetpt_201*.root".
• Another version with the correction factors per era in 2016 and 2017 in one single file, with coarser binning:JetPrefiringMapsperIOV_EOY.root`.

Unfortunately, the files must be downloaded by hand.

At the moment, DAS only includes jets, but one should consider photon and muon maps as well.

Reminder: the prefiring effect only applies to 2016 and 2017 (one run in 2018 seems to be affected as well, but that's all).