Make fabric_util:get_db zone aware
Make fabric_util:get_db zone aware

Use the new mem3:group_by_proximity method to prefer local, then
zone-local nodes over zone-remote nodes.

BugzID: 13470

fkaempfer/couchdb,fkaempfer/couchdb,fkaempfer/couchdb,fkaempfer/couchdb,fkaempfer/couchdb,fkaempfer/couchdb