Replication Znodes Backup Tool

While migrating to 0.96, we recommend deleting old znodes so users not face issues like HBASE-7766, and let HBase create them out of box.
Though HBase tends to store only ephemeral data in zookeeper, replication has a different approach. Almost all of its data (state, peer info, logs, etc) is present in zookeeper. We would like to preserve them in order to not do re-adding of peers, and ensuring complete replication after we have migrated to 0.96.
This jira adds a tool to serialize/de-serialize replication znodes to the underlying filesystem. This could be used while migrating to 0.96.0.