Adjust memilio-generation for flow models and automatic differentiation

[MaxBetzDLR]

Motivation / Current Behaviour

Introduction of flows in issue #511 and the added usage of templates to a lot of classes in issue #894 changed the behavior of the generation package. This results into wrongly generated code. As a temporary fix the reference test data was adjusted.

Additionally the test is slow due to recompiling the c++ code.

Enhancement description

Update memilio-generation to work with new code structure and patterns

Additional context

No response

Checklist

• [x] Attached labels, especially loc:: or model:: labels.
• [x] Linked to project

[reneSchm]

Recompilation could be circumvented by reusing the skbuild directory produced by setup.py. That is, instead of creating a temporary build directory and calling cmake on it from within the test itself, we can probably just set build_dir during the skbuild setup (e.g. via a config file). To keep the build/test split for the CI, we can probably use upload-/download-artifact actions to copy the _skbuild directory from build to test.