Add crowbar-hardware-configured role.

This role is inteded to be used as a checkpoint that downstream roles
can use to indicate that the hardware on the node has been configured
and that the system is ready for provisioning.
Allow certian noderoles to move when a node changes deployments.

This update allows noderoles to move along with their node when moving a
node from one deployment to another, provided the following conditions
are met:

 * The noderole is PROPOSED
 * The noderole has never sucessfully run.
 * All of its children are in the same state

This allows users to edit the RAID configuration on a node before
committing it.
Merge pull request #220 from VictorLowther/add-crowbar-hardware-configured-role

Add crowbar-hardware-configured role.