Adds instructions for deploying instances on real hardware

The following sections have been added to the install-guide:

1. Set of instructions for configuring Neutron to talk to baremetal.
   Flat networking is taken as the usecase. Instructions for using
   other types of networks will be added eventually.
2. Set of instructions for adding the required images to glance.
   Includes instructions for creating the deploy and user images
   using disk-image builder.
3. Set of instructions for creating the baremetal flavor and
   associating the deploy images to the flavor.
4. Instruction for checking that the ipmitool on the openstack setup
   is able to control baremetal's power state.

Change-Id: If45f0f32808308cf2d451a905ca7cd840c81c7d2
Partial-Bug: 1323589