Add generative model metrics notebook (#1771)

Fixes #1770  .

### Description
A few sentences describing the changes proposed in this pull request.

### Checks
<!--- Put an `x` in all the boxes that apply, and remove the not
applicable items -->
- [ ] Avoid including large-size files in the PR.
- [ ] Clean up long text outputs from code cells in the notebook.
- [ ] For security purposes, please check the contents and remove any
sensitive info such as user names and private key.
- [ ] Ensure (1) hyperlinks and markdown anchors are working (2) use
relative paths for tutorial repo files (3) put figure and graphs in the
`./figure` folder
- [ ] Notebook runs automatically `./runner.sh -t <path to .ipynb file>`

---------

Signed-off-by: Yiheng Wang <vennw@nvidia.com>
Co-authored-by: pre-commit-ci[bot] <66853113+pre-commit-ci[bot]@users.noreply.github.com>
Co-authored-by: YunLiu <55491388+KumoLiu@users.noreply.github.com>

Author: 3 people

generation/realism_diversity_metrics/realism_diversity_metrics.ipynb

@@ -79,6 +79,7 @@ doesnt_contain_max_epochs=("${doesnt_contain_max_epochs[@]}" 04_integrating_code
 doesnt_contain_max_epochs=("${doesnt_contain_max_epochs[@]}" bending_energy_diffusion_loss_notes.ipynb)
 doesnt_contain_max_epochs=("${doesnt_contain_max_epochs[@]}" mask_augmentation_example.ipynb)
 doesnt_contain_max_epochs=("${doesnt_contain_max_epochs[@]}" maisi_inference_tutorial.ipynb)
+doesnt_contain_max_epochs=("${doesnt_contain_max_epochs[@]}" realism_diversity_metrics.ipynb)
 
 # Execution of the notebook in these folders / with the filename cannot be automated
 skip_run_papermill=()