MB-10051: configurable disk and metadata limits

Change-Id: Ie669507b50d190eb550298ee1378977f4a1cbf15
Reviewed-on: http://review.couchbase.org/34265
Reviewed-by: Aliaksey Kandratsenka <alkondratenko@gmail.com>
Tested-by: Aliaksey Kandratsenka <alkondratenko@gmail.com>