Notebook fix and modified some scripts
This pull request **introduces 1 alert** when merging 23389db2bfbb66f34af4fc4bfc3c70d58a37b791 into 1b82b571c2f32e1b109677a67c5820222cb696fe - [view on LGTM.com](https://lgtm.com/projects/g/NVIDIA/NeMo/rev/pr-73b2bd0cd56408059f13b25d589e438f9dcb3fba)

**new alerts:**

* 1 for Unused import This pull request **introduces 1 alert** when merging fa085934cf1e249a38988d8be3420bec67f461c8 into 1b82b571c2f32e1b109677a67c5820222cb696fe - [view on LGTM.com](https://lgtm.com/projects/g/NVIDIA/NeMo/rev/pr-a484d0a7cf244b188356a2d7da6ce0cb8bec3807)

**new alerts:**

* 1 for Unused import
Signed-off-by: nithinraok <nithinrao.koluguri@gmail.com>

* Pytorch Lightening links fix
* renamed get_spkr_emb.py to extract_speaker_embeddings.py 
* Added helper speaker_reco_infer.py example script to get labels from trained speaker recognition model
* Added get_hi-mia.py script. (use to be part of old nemo -> used in tutorial) 