openstack.md

* Re-enable ansible_ssh_pipelining as expected for the cluster.yml
* Do not use 'all' wildcasts for hosts, limit only to k8s-cluster, etcd,
  calico-rr groups instead. Other nodes in inventory are out of Kargo
  scope and it's up to users how to manage them.

Signed-off-by: Bogdan Dobrelya <bogdando@mail.ru>