index.md as index of the site

_config.yml

 # in _config.yml
 title: "3IA Health Data Hub - Workshop on heterogeneous data and Federated Learning"
 logo: "assets/img/logo.jpg"
+only_build_toc_files: true
+exclude_patterns: [_build, Thumbs.db, .DS_Store, "**.ipynb_checkpoints", "README.md"]
 execute:
   execute_notebooks: "off"
\ No newline at end of file