add readme for MONAI + Fed-BioMed integration for federated learning

[mvesin]

Fixes # .

Description

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

Checks

• 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>