Add a script to create an EDM4hep file making use of the complete datamodel

[jmcarcell]

BEGINRELEASENOTES

• Add a script to create an EDM4hep file. The script is in python and can be called like python createEDM4hepFile.py. I have tried to make use of every member and relation in the data model. The purpose is to have something that can create quickly an EDM4hep file and because the script is in python no compilation is needed, hopefully lowering the barrier to get to an EDM4hep file. People can adapt it to their needs or use it as an example for testing, debugging, etc.

ENDRELEASENOTES
For the question, "should this be a test?" I don't have a strong opinion but I think it would have less visibility than in /scripts

[peremato]

Great! well done

For the question, "should this be a test?" I don't have a strong opinion but I think it would have less visibility than in /scripts
A test can be created that uses the script in /scripts

Two questions (perhaps are trivial)

• how do you choose the ROOT format (TTree or RNTuple)?
• Why do you need cppyy.ll.static_cast?

[jmcarcell]

Great! well done

For the question, "should this be a test?" I don't have a strong opinion but I think it would have less visibility than in /scripts
A test can be created that uses the script in /scripts

Two questions (perhaps are trivial)

* how do you choose the ROOT format (TTree or RNTuple)?

* Why do you need `cppyy.ll.static_cast`?

I added an option --rntuple to save to RNTuples. For the second question it seems it's a problem in cppyy maybe, see: #270 (the conversion operator is not being used from the mutable to the non-mutable types)

[tmadlener]

We should add a run of this script to CI, to make sure it always works.

[tmadlener]

We either need to add the podio that we have used for building here as well to PYTHONPATH, or we have to do it in the workflow file in the step where we build and install podio. CI is partially failing, because it picks up an older version of podio from the LCG stack:

https://github.com/key4hep/EDM4hep/actions/runs/10045234420/job/27762066625?pr=272#step:4:817