High Availability refacto

This PR aims to meet the 3 scenarios we might encounter when deploying openstack in relation with H

  1. Active/Active
  2. Active/Passive (HA and Controller on different hosts)
  3. Active/Passive (HA and Controller on same host)

In order to make it work, you'll need to rely on this fork of puppetlabs-haproxy (https://github.com/Spredzy/puppetlabs-haproxy/tree/do_conf_on_enable_false) since currentyl the one offered does not handle active/passive setup.