S3 bucket replication API

Create replication between different buckets in a storage cluster with Ceph Object Gateway configuration.

The S3 bucket replication API is implemented, and allows users to create replication rules between different buckets. While the AWS replication feature allows bucket replication within the same zone, Ceph Object Gateway does not allow it at the moment. However, the Ceph Object gateway API also added a Zone array that allows users to select to what zones the specific bucket is synced.