Add ansible prov for OOD2.x roles.

- Set build_instance_name to match the hosts defined in OOD play
- Currently, use_proxy defaults to true for all connection types.
  In the future, this option will be changed to default to false
  for SSH and WinRM connections where the provisioner has access
  to a host IP. Further details in documentation
  https://www.packer.io/plugins/provisioners/ansible/ansible#use_proxy
- As stated in docs link above use_proxy will be set to false in
  the future ansible versions. Currently we set it to False.
  Provide a valid username & ssh key to the ansible provisioner
  directly or make sure that username and ssh key being used by
  ssh communicator will work for your needs. We chose option 2.