MB-9343 assign repl_type to upr for new buckets in 3.0 cluster

for now only if enable_upr app env variable is set to true.

Change-Id: Icd3cf3cef4c7c3b0c2dbaf33e71e08144592f002
Reviewed-on: http://review.couchbase.org/33514
Tested-by: Artem Stemkovski <artem@couchbase.com>
Reviewed-by: Aliaksey Kandratsenka <alkondratenko@gmail.com>