CI: use kubevirt.core dynamic inventory

This allows a single source of truth for the virtual machines in a
kubevirt ci-run.

`etcd_member_name` should be correctly handled in kubespray-defaults for
testing the recover cases.

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

@@ -12,6 +12,9 @@ metadata:
     kubevirt.io/domain: "{{ test_name }}"
     ci_job_id: "{{ ci_job_id }}"
     ci_job_name: "{{ ci_job_name }}"
+    {% for group in kubespray_groups -%}
+    kubespray.io/{{ group }}: "true"
+    {% endfor -%}
   # leverage the Kubernetes GC for resources cleanup
   ownerReferences:
   - apiVersion: v1