Initial migration of BPHY Derivations to master
I copy the DerivationFrameworkBPhys package from 21.2 and do a lot of migration to AthenaMT. Some of the simpler derivations will now run. Some code is disabled until further work can be done.
Notable changes:
- ThinningSvc migration
- Removal of unused classes
- Reco_diMuTrk Reco_diMuTrkTrk and Reco_MuMu are now combined into Reco_Vertex
- Variable datahandle and decoration migrations (incomplete)
- Python3 changes