converter script: Add an option to generate an EDM4hep input + converter instead of LCIO input

This is mainly an idea at this point that came up while preparing a tutorial. It would be nice to have a flag in the converter script to not generate an `LcioEvent` algorithm, but rather a `PodioInput` and a converter (that would need to be attached to the first wrapped processor).

It is obviously possible to do all of this manually after the conversion, but it would be a nice feature. Unless, we decide that this is not worth the effort.

Start by locating the converter script and examining how it currently generates the LcioEvent algorithm and attaches the first wrapped processor. Define the flag's expected EDM4hep output using PodioInput and a converter, then verify that generated configurations work in the tutorial workflow.

Written by the indexing model from the issue text.