Add ClearML experiment management tutorial (Project-MONAI#1489)

### Description
Add tutorial which demonstrates ClearML experiment management using
MONAI's built-in `ClearMLImageHandler` and `ClearMLStatsHandler`.

### Checks
<!--- Put an `x` in all the boxes that apply, and remove the not
applicable items -->
- [x] Avoid including large-size files in the PR.
- [x] Clean up long text outputs from code cells in the notebook.
- [x] For security purposes, please check the contents and remove any
sensitive info such as user names and private key.
- [x] 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
- [x] Notebook runs automatically `./runner.sh -t <path to .ipynb file>`

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Signed-off-by: revital <[email protected]>

Author: pollfly

README.md

@@ -146,6 +146,9 @@ An example of experiment management with [Aim](https://aimstack.io/aim-monai-tut
 An example of experiment management with [MLFlow](https://www.mlflow.org/docs/latest/tracking.html), using 3D spleen segmentation as an example.
 ##### [MONAI bundle integrates MLFlow](./experiment_management/bundle_integrate_mlflow.ipynb)
 An example shows how to easily enable and customize the MLFlow for experiment management in MONAI bundle.
+##### [ClearML](./experiment_management/unet_segmentation_3d_ignite_clearml.ipynb)
+An example of experiment management with [ClearML](https://clear.ml/docs/latest/docs/), using 3D Segmentation with UNet as an example.
+
 
 #### <ins>**Federated Learning**</ins>
 ##### [NVFlare](./federated_learning/nvflare)