[Imprv] Make changes to include project_reference in dynamic inventory for groupping

[patrickschmed]

We're managing multiple customers on our Nutanix env and using "Project" for assigning VMs to a customer.

project_reference.name should be included in the ntnx_prism_vm_inventory.py script to enable grouping by project. We adapted it for our purpose, code snippet:

        if "metadata" in entity and "project_reference" in entity["metadata"]:
            self.inventory.set_variable(
                vm_name, "ntnx_project", entity["metadata"]["project_reference"]["name"]
            )