Move default image logic from DevStack to Ironic
Move default image logic from DevStack to Ironic

This patch is moving the logic setting the default images from DevStack
into the Ironic tree. A TODO was left inline pointing out we can
refactor the logic there after we get this merged and the devstack code
removed.

Change-Id: Id828b41dc44113ce1cd094ce5fc245989699d4ff

openstack/ironic,openstack/ironic,pshchelo/ironic,SauloAislan/ironic,NaohiroTamura/ironic,pshchelo/ironic,NaohiroTamura/ironic,SauloAislan/ironic