==== fixed cellID of SimTrackerHits for ILDExSimu examples

   - using the VolumeID set for PlacedVolumes to be the
     superset of the physVolIDs of the complete 
     path from the world volume
     - as the internal encoding in DD4hep starts with
       the MSB we have to transfer it into the LC
       convention using the BitField64 class

     -> see code in Geant4TrackerSD
        ( should go to a standalone/utility function)
   
   - adopted VXD and SIT to set the complete
     set of the canoncial cellID: system,side,layer,module,sensor


--Ths lin, and those below, will be ignored--

M    DDG4/src/Geant4TrackerSD.cpp
M    DDExamples/ILDExDet/compact/ILDEx.xml
M    DDExamples/ILDExDet/src/compact/ILDExSIT_geo.cpp
M    DDExamples/ILDExDet/src/compact/ILDExVXD_geo.cpp