Add Stan's Durations and Gaussian Embedding
This pull request **introduces 10 alerts** and **fixes 6** when merging f44c492473364106bcc445a9b723ed3c961f2ac3 into cf23c451ecdc8bd8b0d2bd48103717121780e989 - [view on LGTM.com](https://lgtm.com/projects/g/NVIDIA/NeMo/rev/pr-0671fc7ef505fcdfab6011715546b767428230d0)

**new alerts:**

* 9 for Unused import
* 1 for Unnecessary pass

**fixed alerts:**

* 6 for Unused import