npsim - a ddsim wrapper

Created a wrapper on ddsim and copied a modified DDG4.py which uses Geant4Output2Podio instead Geant4Output2ROOT. npsim is just like ddsim but it uses dd4pod.

src/GenericDetectors/calorimeters/compact/scripts/run_example

 #!/bin/bash
 
-ddsim  --runType vis  --enableG4GPS \
+npsim  --runType vis  --enableG4GPS \
    --macroFile macro/gps.mac \
    --compactFile $1 \
    --outputFile test_calorimeter.root  || exit