Fix mt sim

Fixed run time problems for OscarMTProducer. The interface layer between RunManagerMT and user actions was incomplete. ExceptionHandler is doing nothing, likely this is an obsolete class and will be removed later.

Because I have started from 7_2_X-GEANT10 branch git shows below all 250 commits from 7_0_X up to now. In reality only 14 files are changed. All these changings are not affect main production - validation results should be identical.