Add - script to return all current zookeeper nodes

 - get_zookeeper_endpoints.sh returns connection info about zookeeper
 servers registered in etcd
Add - added module to get coreos machines info

- more modules might need info about coreos machines therefore I've
created simple bash/awsk based get_coreos_machines module
Merge branch 'feature/zookeeper_ha' into develop
Adding registry units and ansible playbook
Added documentation
Merge branch 'feature/docker_registry' into develop
Add docker registry

- registry and zookeeper are deployed using ansible
Fix - add /etc/hosts and fix editing from registry playbook
Merge branch 'hotfix/etc_hosts_edit' into develop
Registry is utilized by zookeeper images

- Registry images are in variables
- zookeeper image is pushed to registry
- zookeeper unit leverages docker image names from variables
- /etc/hosts is changes even on localhost because build/push is
performed on localhost