MB-8295: Start a couch_set_view instance for dev views

Development views should use the partition aware set views,
but with a single partition. This commit starts the manager
for those development views. It shouldn't intefere with
the existing ones.

More code will be moved to the new dev views in subsequent
commits.

Change-Id: I0f1f99552a5dc9dfe323aaf1961f5160c2e5cd7d
Reviewed-on: http://review.couchbase.org/26476
Reviewed-by: Filipe David Borba Manana <fdmanana@gmail.com>
Tested-by: Filipe David Borba Manana <fdmanana@gmail.com>