Move libconflate to cmake/

Change-Id: Iff32899060475a6578d91ec073df644e8dbfda4e
Reviewed-on: http://review.couchbase.org/29182
Reviewed-by: Trond Norbye <trond.norbye@gmail.com>
Tested-by: Trond Norbye <trond.norbye@gmail.com>