Adding PathResolver for new 3D PU correction
This MR implements a correction to the config file path in the 3D PU to be able to read files that are located in the CalibArea. The implementation is done as in other classes within JetCalibTools.
Marking as urgent because we need this correction to proceed with the Jet/Etmiss precision recommendations.
Also tagging @sschramm @dportill @jroloff @mleblanc for their information