Expose apiGroup property

[stan-sz]

For k8s resources like see how apiGroup could be used in a real-world scenario:

resource clusterRole 'rbac.authorization.k8s.io/ClusterRole@v1' = {
  metadata: {
    name: 'cluster-role'
  }
   rules: [
     {
       apiGroups: [
       ]
       resources: [
        ]
       verbs: [
        ]
     }
   ]
}

resource crb 'rbac.authorization.k8s.io/ClusterRoleBinding@v1' = {
  roleRef: {
    apiGroup: 'rbac.authorization.k8s.io' // ideally: clusterRole.apiGroup
    kind: clusterRole.kind
    name: clusterRole.metadata.name
  }
  metadata: {
    name: 'cluster-rolebinding'
  }
  subjects: [
    {
      kind: 'Group'
      name: clusterReaderGroupId
    }
  ]
}