Ported RelatedInfoNamed.h from 2018-patches
Copied Phys/DaVinciTypes/Kernel/RelatedInfoNamed.h from 2018-patches
This is needed for 2017-patches of B2XMuMu Stripping where new RelInfoTools were introduced (i.e. Phys/IsolationTools/src/RelInfoBKstarMuMuHad.* in the Stripping package)