Tensor python binding: implementation management design issue

https://gitlab.eclipse.org/eclipse/aidge/aidge_core/-/blame/main/python_binding/data/pybind_Tensor.cpp#L99 Storing a reference on a unique_ptr is meaningless. Either we want to share ownership of implementation with the python wrapper or we guarantee that, when the original Tensor is destroyed, the wrapper is not used anymore. The first scenario implies the use of a shared_ptr, in the second case, storing a raw pointer would be equivalent with a bit of bookkeeping to avoid dangling pointer access. Faisability of scenario 2 depends on the way the wrapper lifetime is handled with respect to the wrapped object one.