Optimize venv activation (mapper)

• Distinguish model into components with dedicated features (e.g. predict, explain, map) in order to have a component encharged of mapping with fewer dependencies than the others.
• Generalize custom_dependencies usage in dags/invocation/tasks/run_computation.run_computation_in_venv(dag_params: InvocationDAGParams, deployment: dict).
• Find a way to make this change backward compatible with already existing models.