Generation of event time-stamps according to GRP SOR/EOR times. The method to active...

Generation of event time-stamps according to GRP SOR/EOR times. The method to active it is AliSimulation::UseTimeStampFromCDB(). From the moment the time-stamps are generated using a flat distribution between SOR and EOR time-stamps. The way to access the time-stamp is via the AliHeader, namely runloader->GetHeader()->GetTimeStamp(). The time-stamps are not yet propagated to the simulated raw data. This will be done as a second step related to bug#53025