Call Cargo configure step from CargoPythonPackage

[Flamefire]

That does additional configuration required for Rust crates with #3995

[boegel]

@Flamefire Can you clarify (in the PR description, and with a comment in the easyblock) why this is needed?

[Flamefire]

It was "just missing". So the question worth a comment would rather by why it does not need to be this way.

If we don't do this we only call the configure_step of PythonPackage, not of Cargo which isn't what we want, do we?

IIRC how the Python MRO works we could always use super().configure_step() and it would end up calling each configure method exactly once. But that would need to be done in the whole stack, i.e. at least also in PythonPackage which seems like a too big of a change right now. We'd likely need to test all easyblocks deriving from PythonPackage and add a (dummy) configure_step in EasyBlock

Currently MRO will find PythonPackage.configure_step´ and runs that. And as that doesn't call any other configure_step` none is run.