converter script: Replace InitDD4hep processor on the fly with relevant services

[tmadlener]

Currently mainly an idea that came up while preparing a tutorial.

As stated here it is now possible to replace this wrapped processor with the GeoSvc and (potentially) the TrackingCellIDEncodingSvc. It should be possible to do this on the fly if the relevant processors are detected.

This would be a nice improvement to avoid some manual editing of the converted script. Putting this here also for a discussion on whether we think this is worth the effort.