New deploy driver using ansible for node bootstraping

Current use mode of IPA consists of clearly defined steps (clean disk, configure raid, download image etc). It should be possible to define those steps as parametrized configuration units and use existing configuration managers to perform those steps on the BM node during bootstrap process.

Ansible is already mature enough configuration management tool. As it is written in Python, it seems like a nice fit to OpenStack and Ironic in particular. Moreover, its minimal requirement is presence of Python and SSH access on node to be configured, so almost any modern Linux image can be used as bootstrap image without a need of any specific agent inside.

It is proposed to create a new deploy driver that would use Ansible for node configuration. Each appropriate step of node provision then is defined as Ansible role.