Add a page to the `dataset` documentation

[maks-sh]

📚 Documentation

There should be a table with approximately the following columns:

• Dataset name,
• what is the task,
• the share of the treatment,
• the share of the target,
• a link to the API function
• link to EDA notebook,
• In which tutorials were used,
• Source

[rishawsingh]

Do you want this new page in this (scikit-uplift/sklift/datasets/ )file path?

[maks-sh]

Good question👍

Let's add it to User Guide: docs/user_guide/datasets.rst

It is important to add a link to new file in the docs/user_guide/index.rst