DerivationFrameworkBPhys: Refactored BPHY12 derivation.
The BPHY12 derivations has been completely rewritten. It fixes an issue with the old derivation version (missing BdBar candidates) and adds specific metadata. Also, the code has been cleaned up and made ready for addition of other semileptonic rare B-decays when needed (not now - no manpower for the analysis of the other channels)
The derivations has been tested on signal MC AODs and few real-data events. The output is as expected and no problems has been identified.