Implement Keystone domain creation

Keystone domain has to be created for Heat. This patch implements this
via helper script [1] since we don't have support for Keystone v3 API
in puppet-keystone yet. This implementation should be refactored as soon
as we will have v3 API available in puppet-keystone. For more info
please check [2].

[1] https://github.com/openstack/heat/blob/master/bin/heat-keystone-setup-domain
[2] https://bugzilla.redhat.com/show_bug.cgi?id=1076172