Hadrons merge

[peter-mckeown]

Splitting part 1 from MR! 4:

Adds the possibility to configure models for hadronic shower simulation (including placement in ECAL + HCAL). So far testing has been performed for single particle events loaded from HDF5

[tmadlener]

I think this looks good in general. there are a few (more or less) minor comments below for some specifics.

Some other general remarks:

• There is quite a few places where commented code is still included. I would have a preference for removing that
• There are a few places where std::cout is used. Can we change those to use the dd4hep logging facilities?

In the end the PionCloudsModel is rather similar to the CaloCloudsTwoAngleModel and we could think about trying to factor out the similarities of those into a separate class. But that is definitely not in the scope of this PR for me.

[peter-mckeown]

Thanks a lot for the review @tmadlener ! I think all your comments should be resolved now- I also went through and replaced all instances where std::cout is used with dd4hep logging facilities. Therefore I hope this will resolve Issue 1 as well.
I agree- there is a lot of commonality between the PionClouds loading and CaloClouds. I think as this is currently more about the functionality for including hadron showers it is probably best to wait with a common class as you say, especially because this is currently just loading from a hdf5 file rather than actually running inference.