Improved ModelConfiguration serialization

[SimBe195]

This PR adds a new version of the build_config_constructor_serializers function. Compared to the previous one, now also Enum values as well as list, tuple and dict values with non-primitive elements inside are serialized. This is useful for example for the GenericFrontendV1 which use a sequence of FrontendLayerType enum values for the layer ordering. This wouldn't work with the original function but is possible with the v2 version.

Another change is that the de-duplication of the recognized imports now works properly and imports get sorted.

The changes are realized in a v2 function because they can affect the hash of the serializer objects and thus would break existing setups.