Enable delete_times on replication

Creating this to track how/when we update replication to make use of the DCP changes in the parent MB so that replicas copy the tombstone times when replicas are built.

The simplest way to enable the new DCP is to consider it the same as when we enabled XATTRS, waiting until all nodes are capable of sending/receiving the updated delete packet and then restarting all DCP producers/consumers with the new open flag.