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
Refresh flag in optimize is problematic, since the shards refresh is allowed to execute on is different compared to the optimize shards. In order to do optimize and then refresh, they should be executed as separate APIs when needed.
closes#3690