* [squash] Staging autotuning v4
Co-authored-by: NCheng Li <pistasable@gmail.com>
Co-authored-by: NMinjia Zhang <minjiaz@microsoft.com>
Co-authored-by: NOlatunji Ruwase <olruwase@microsoft.com>
Co-authored-by: NJeff Rasley <jerasley@microsoft.com>

* add new extra, guard xgboost, cleanup dead files (#268)

* Fix autotuning docs (#1553)

* fix docs

* rewording the goal

* fix typos

* fix typos (#1556)

* fix typos

* fix format

* fix bug (#1557)

* fix bug
Co-authored-by: NJeff Rasley <jerasley@microsoft.com>
Co-authored-by: NMinjia Zhang <minjiaz@microsoft.com>
Co-authored-by: NOlatunji Ruwase <olruwase@microsoft.com>