Make CbmEvent, CbmDigiData and CbmDigiEvent streamable for mCBM MQ devices

- Add copy constructor to CbmEvent
- Define DigiData types and add members for the other CBM detectors in CbmDigiData(!MUCH beamtime digi usage!)
- Add vector of CbmEvents, all DigiData types, CbmDigiEvent and vector of CbmDigiEvent to LinkDef to get ROOT streamers (needed to write to ROOT file)