Draft: Retagging for V0 information

Configuring InDetV0Finder for retagging

This MR is not to be merged. My goal is to incorporate the InDetV0Finder in retagging, which requires a few custom configuration files to be made in order to set up the InDetV0FinderTool, the V0Tools, and the TrkVKalVrtFitter (the config file for this last one may already exist elsewhere, I made a custom config regardless).

Issues

I have been experiencing issues configuring the underlying Extrapolator of the V0Tools tool. The error message references that the AthCheckedComponent has no job properties, and thus throws an error. The config file I use to set up the Extrapolator is from AtlasExtrapolator, using syntax identical to how other tools configure the same tool. My only indication for why the V0Tools would differ from, say, the BTagTrackToVertexTool (which sets up and retrieves the Extrapolator successfully), is in how the underlying C++ code declares the ToolHandle of the IExtrapolator tool.

Next Steps

The course of action I'll pursue first is to compare the other tools that declare this ToolHandle, which successfully manage to setup and retrieve the Extrapolator for their purposes. As mentioned above, the BTagTrackToVertexToolConfig manages to do this, but what about the others? The answer could lay in how they declare the ToolHandle vs. how the V0Tools declares it. I'll then proceed with making changes to the V0Tools locally.

Feedback

Any feedback on the configuration files is welcome. I've set up the code such that you can build it with the setup-athena.sh script (i.e. I altered the CMakeLists as needed). The InDetV0FinderAlgConfig is added to the end of the retag.py script, which should schedule the algorithm in retagging, assuming all the underlying dependencies are configured and retrieved successfully (the present issue).