Add Fake tau Task force variables

New tool to add variables for the Tau Fake Task Force both in Derivations and THOR.

• Added a TauRecTool to add tau width variable to xAOD
• Added TauAODProcessor configured to run over AOD and that only loads this tool
• Added call in DerivationFrameworkTau/TauCommon.py to load the TauAODProcessor.
• Added variable in **DerivationFrameworkTau/TauJetsCPContent.py

All problems are now solved, thanks in particular to @fscutti

@martindl : Do you want to remove the same variable from DerivationFrameworkSUSY in the same MR?