Update particle flow references for Run 4 HL-LHC
This MR updates the Run 4 HL-LHC configuration to use the PFlowCellEOverPTool with the latest json input references on cvmfs.
Two new flags are introduced in python - one to specify the location of the references and another to toggle usage of the previous legacy e/p tool. The latter will be removed in the near future, along with the old c++ reference tool, once final validation is done on larger samples.
A number of obsolete python flags were also removed.
Changes in Run4 output for particle flow and anything that depends on particle flow are expected. No changes in Run 3 output are expected.
A protection against bin energies of zero was also added to avoid FPE when dividing by zero - up until now the new bin strategy was not used, so this had not been spotted previously.