Format an images properties and tags
Format an images properties and tags

Currently, these properties are each top level keys, they should
all be under a single 'properties' field. Secondly, the tags are
kept as an array, but can be shown as a comma separated string.

Change-Id: Ic769c657a86e768fee38acc40434c377de70a7bc

dtroyer/python-openstackclient,dtroyer/python-openstackclient,redhat-openstack/python-openstackclient,BjoernT/python-openstackclient,openstack/python-openstackclient,redhat-openstack/python-openstackclient,BjoernT/python-openstackclient,openstack/python-openstackclient