GitLab

* Ported DeepSpeed overview.

* Renamed subsection

* Formatting table of contents

* initial import of Megatron tutorial

* Grammatical edits, formatting, and paths.

* formatting and data download instructions

* formatting tutorial

* formatting tutorial

* formatting tutorial

* formatting tutorial

* formatting tutorial

* formatting tutorial

* new perf chart

* removing TODO

* adding pointer to tutorial

* edits

* azure to low bandwidth
Co-authored-by: Samyam Rajbhandari <samyamr@microsoft.com>