TauAnalysisTools: clean up tau selection tool

Hello,

This MR is cleaning up the tau selection tool. The most notable change is the renaming of EleRNN to EleID to be generic regarding the algorithm used for electron-faking-tau rejection (this renaming is already done for efficiency correction tools). If we deploy e.g. a deep set NN instead of a RNN later, we'll just need to extend an enum instead of duplicating code as we did in R21. A new directory was created in the calibration area (will appear at /cvmfs/atlas.cern.ch/repo/sw/database/GroupData/TauAnalysisTools/00-04-00/), where we'll start putting R22-specific calibration files. In this MR, the only new such file is recommended_selection_r22.conf which holds the new default tau selection:

SelectionCuts: PtMin AbsEtaRegion AbsCharge NTracks JetIDWP EleIDWP

PtMin: 20
AbsEtaRegion: 0; 1.37; 1.52; 2.5
AbsCharge: 1
NTracks: 1; 3
JetIDWP: JETIDRNNMEDIUM
EleIDWP: ELEIDRNNLOOSE

Soft links to the latest available R21 files (from the 2019-summer recommendations) have been created as placeholders until we get R22 Run2 recommendations.

Also, TauAnalysisAlgorithms/data/tau_selection_noid.conf used to apply EleRNNWP: ELEIDRNNLOOSE which I guess is not intended as it's called "noid", so I replaced it with EleIDWP: ELEIDNONE.

Tagging @qbuat , @dta , @ghamity , @ademaria .

Cheers, Bertrand