CBQE-1642: Add configurable logs& stats for server

Change-Id: Iff5bf766c24efcf4e7b2b6d493247c1a408f4bdb
Reviewed-on: http://review.couchbase.org/30962
Reviewed-by: Tommie McAfee <tommie@couchbase.com>
Tested-by: Ketaki Gangal <ketakigangal@gmail.com>