feat: GeoID hook from python & ODD hook

[benjaminhuth]

This PR adds a mechanism to add a geometry identifier hook directly from python, e.g. in odd.py (thanks @paulgessinger for the suggestion with the py::object). So there is no need to awkwardly define a ODD-specific hook somewhere in the C++ code.

I think this is not breaking, even though it changes Acts::GeometryIdentifierHook from a typedef to a std::function to a virtual baseclass. However, in docs/versioning.rst the Geometry module is not defined as "subject of the versioning".

The extra-bits in the ODD are now set like this:

Thanks also @Corentin-Allaire for the preparing work! I would suggest to close #1696 after this is merged.

cc @asalzburger