This has been very trappy. Rather than continue to allow buggy behavior
of having upgrade/optimize requests sidestep the single shard per node
limits optimize is supposed to be subject to, this removes
the ability to run the upgrade/optimize async.
closes#9638
This commit does the following:
* Add the new API at the rest layer, being backed by the optimize API
with upgrade flag, and segments api to find upgrade status.
* Add `upgrade` flag to optimize API, and deprecate `force` flag (will
remove in master)
* Add test for both synchronous and async upgrade
closes#7884closes#7922
Ryan Ernst
Clinton Gormley