Modernized UT code and adapted to drop of UT base classes
Part of the set of MRs LHCb!3369 (merged), Lbcom!594 (merged), Rec!2670 (merged), !375 (merged)
Part of the set of MRs LHCb!3369 (merged), Lbcom!594 (merged), Rec!2670 (merged), !375 (merged)