Ceilometer API may want to expose

The ceilometer-api process may need to expose endpoints used for self monitoring. These endpoint are not exposing data, just the health of the process to a management system or a load balancer. These external systems may not use keystone authentication.
The goal of this blueprint is to expose URLs that do not require keystone authentication.
Currently all URLs are filtered by keystone-auth middleware.
This change is to use delegated auth supported by keystone middleware so that ceilometer-api can be configured to allow certain URLs to execute without a keystone token.