Add support for openstack_extras repo mgmt

This patch begins the migration away from the
homegrown openstacklib and towards the stackforge
openstack_extras project. Repo management is changed
to hash based, which allows all yumrepos to be managed
in a single location.
Merge pull request #42 from michaeltchapman/librepo_to_extras

Add support for openstack_extras repo mgmt
Add ELK support

Elasticsearch, logstash and kibana modules added. The
ones from the forge are deeply flawed, new ones have been
written under github.com/michaeltchapman

Logstash-forwarder is used, and sample TLS certs provided.

Existing load balancing cluster is used to proxy ES for Kibana
users.

Change-Id: Ica300664b2c5b3c94f47a4b40c9be88adc5a7eae