[Doc] round_robin_gradients (#1261)
* Fix docstring
* Make screenshots clickable for easier viewing
* Navigation menu in alphabetical order; More clicable screenshots
* Rename 1Cycle doc
* Tweak naming
* Remove no longer used flag
* ZeRO3 Offload release
* Single GPU results
* Rearrange figures
* Single GPU text
* tweak intro
* zero3-offload section
* Add asynchronous i/o docs
* Fix print_per_steps doc
* Document round_robin_gradients
* Tweak description
* Trigger CI
