add new endpoint type "hawkular" to read inventory and metrics

[jmazzitelli]

When the Hawkular Java Agent is deployed in OpenShift, that agent won't have permissions to write to Origin Metrics. To support running the Hawkular Java Agent in OpenShift and using Origin Metrics, it will provide its metric and inventory data to HOSA. HOSA needs to know how to query the Java Agent for this data. Once it gets that data, HOSA needs to write that metrics and inventory data to Origin Metrics.

See http://lists.jboss.org/pipermail/hawkular-dev/2017-April/003832.html

The Hawkular Agent needs to add support for this - see its JIRA issue here: https://issues.jboss.org/browse/HWKAGENT-170