Cetus is a based on openstack solution of k8s on openstack, and it can be
operated through kesytone to automatically create multiple instances, and
automatically deploy multiple k8s clusters on instances. Cetus Datasource
include Cetus entities(cetus.cluster, cetus.pod).
Implements: blueprint add-cetus-datasource
Change-Id: I2057c901c8e28e1d61c506dcd8790d404817aaa8