Create networks sections for OpenStack provider

The first step at attempting to address issue #637 and issue #791
requires the ability to provision specific networks within a VM.

Now, a user will be able to select a specific network uuid with the
following configuration::

    networks:
        - 4402cd51-37ee-435e-a966-8245956dc0e6

Note: You are able to pass multiple network UUIDs to openstack too.

Signed-off-by: Paul Belanger <paul.belanger@polybeacon.com>