MB-12564: introduced internal api for list of node services

Change-Id: Idd094e105ce9a0da079358bd593b5fac77a247a1
Reviewed-on: http://review.couchbase.org/42868
Reviewed-by: Artem Stemkovski <artem@couchbase.com>
Tested-by: Aliaksey Kandratsenka <alkondratenko@gmail.com>