MB-9453: Parallelize accesslog loading phase

Warmup's accessLog loading phase can take
advantage of GIO. To do so, access scanner will
need to set up a shard number of access logs
rather than the one complete log. There by access
scanner will also run access scanning phase
at shard level parallely.

Now in the warmup's accessLog loading phase
seperate threads are set to take on each access
log.

Change-Id: I76bdf4dc855cf1c124f93d7ff7ed71443cecd6fd
Reviewed-on: http://review.couchbase.org/30121
Reviewed-by: Chiyoung Seo <chiyoung@couchbase.com>
Tested-by: Chiyoung Seo <chiyoung@couchbase.com>
MB-8988: Sequence numbers are assigned through the CheckpointManager

Change-Id: If3fdf08e1091ad36ea8bcd30b10cd3803db009ae
Updates to add stream response api based on memcached changes

Change-Id: I46d0022f8cdd86be3399c646afadcba629ef6b56
Add couch_notifier_enabled engine parameter

This allows us to disable couchdb notifications so that
we can run memcached with ep-engine and couchstore

Change-Id: I9a3c50443ff35b7a602803f229ea0b0b793b7125
UPR consumer add_stream command.

Change-Id: I40332293a9ae5df0c366297041b4d8d3fa871668