SGD QA
This pull request **introduces 21 alerts** when merging 0af0bc70ad4a47e06067aa02ea4ada5a86168cc2 into 297a8bdbb0370a51cb74a41288025befd9cd2392 - [view on LGTM.com](https://lgtm.com/projects/g/NVIDIA/NeMo/rev/pr-40f8e76f758db09b08253434d7944ca47edbd50f)

**new alerts:**

* 16 for Unused import
* 5 for Unused local variable This pull request **introduces 21 alerts** when merging 4c9e21e39c492dc583a8b9c7b277d0a83ec01e9d into 297a8bdbb0370a51cb74a41288025befd9cd2392 - [view on LGTM.com](https://lgtm.com/projects/g/NVIDIA/NeMo/rev/pr-c09ce5ec6b80d84c152294588eec12d5dca3d875)

**new alerts:**

* 16 for Unused import
* 5 for Unused local variable This pull request **introduces 8 alerts** when merging 9dae1ddf19acb06084cbcb1121c03668b76c9908 into 297a8bdbb0370a51cb74a41288025befd9cd2392 - [view on LGTM.com](https://lgtm.com/projects/g/NVIDIA/NeMo/rev/pr-0bff3a176e7685d9e9b349b9cce8e6e60d51c917)

**new alerts:**

* 8 for Unused import Which paper was implemented here? @chris-boson  a modification of https://arxiv.org/pdf/2006.09035v1.pdf
SGD QA model
* added ci test
* added documentation