extend tauRec to run using PFlow jets as seed in R22

This MR will allow to use PFlow jets as seed for tau reconstruction in R22; a test of the reconstruction can be done using:

https://gitlab.cern.ch/atlas/athena/-/blob/main/Reconstruction/tauRec/share/tau_standalone_EMPFlow_ESDtoAOD.py

(also updated in this MR).

The main change in the reconstruction code would be an extension to use FlowElements constituents from the seedJet

Tagging @martindl, @sineadf and @dta