Allow adl in time
Adapted LHCb code to merge request gaudi/Gaudi!290 (merged) of Gaudi
This merge request fixes a missing operator for time comparison, which was thus declared on hte LHCb side. Now that it is declared in Gaudi, the LHCb version was conflicting
Note that this should not be merge before the involved Gaudi merge request, neither before !615 (merged) as it stands on top of it