BaSyx-Core: Deprecate ModelReference

[s-heppner]

We use the pattern described in #264 to refactor class ModelReference.

3 new global methods

• get_identifier_from_referable(s: Referable, store: AbstractObjectProvider): Retrieve the class Identifier of the class Identifiable object, which is referenced or in which the Referable is contained.

• resolve(reference: Reference, store: AbstractObjectProvider): Follow the :class:~.Reference and retrieve the :class:~.Referable object it points to. Make sure that reference.type == "ModelReference" (or similar)

• model_reference_from_referable(referable): Construct a Reference to a given Referable AAS object

• Then ModelReference can be deleted

[s-heppner]

We decided for going towards a different architechture. Instead of semantically patching the generated aas-core SDK, we will build our functionality on top of it.

Since we will loose backward compatibility, we created a new project called BaSyx-Python-Framework.

This Issue is therefore deprecated.