CI: adapt packet-ci role to act as a molecule provisioner

To work with molecule, we need to use the name provided by molecule_yml
in inventory.

Inject the name in the VirtualMachineInstance (with a default to handle
non-molecule scenario) and get it back as part of inventory).

Account for no ansible groups

tests/cloud_playbooks/roles/packet-ci/templates/vm.yml.j2

@@ -7,11 +7,11 @@ metadata:
   annotations:
     kubespray.com/ci.template-path: "tests/cloud_playbooks/roles/packet-ci/templates/vm.yml.j2"
     ansible_groups: "{{ node_groups | join(',') }}"
+    inventory_name: "{{ name | d(cloud_image ~ '-' ~ index) }}"
     # This does not use a dns prefix because dots are hard to escape with map(attribute=) in Jinja
   labels:
     kubevirt.io/os: {{ cloud_image }}
     kubevirt.io/size: small
-    kubevirt.io/domain: "{{ test_name }}"
     ci_job_id: "{{ ci_job_id }}"
     ci_job_name: "{{ ci_job_name }}"
   # leverage the Kubernetes GC for resources cleanup