workbooks/deployment: add support to filter nodes when running Ansible
workbooks/deployment: add support to filter nodes when running Ansible

In run_ansible task, adding support to filter nodes with limit_hosts
(--limit option in Ansible), so we can call the workbook with the desire
to run Ansible only on certain hosts (e.g. scale down).

Change-Id: I1aa086cc706110905b7a45a765d67d01ee90434e

openstack/tripleo-common,openstack/tripleo-common