Allow the user to set annotations in the CRDs of the following operators which will then be set on
the resulting Pods (Deployments, StatefulSets and so on).
Operators:
* Cassandra
* Ceph
* CockroachDB
* EdgeFS
* Minio
* NFS

The Annotations related structures have been added to the
rook.io/v1alpha2 pkg.
Signed-off-by: Alexander Trost <galexrt@googlemail.com>