delta recovery UI

Change-Id: I262e7aef48d67683a17c1e20c4ecab354db1b93f
Reviewed-on: http://review.couchbase.org/36660
Reviewed-by: Aliaksey Kandratsenka <alkondratenko@gmail.com>
Tested-by: Aliaksey Kandratsenka <alkondratenko@gmail.com>