Improve README.md

[Windyskys]

This commit replaces the existing README.md with a more comprehensive and user-friendly version.

The new README includes:

• A Table of Contents for easier navigation.
• Detailed instructions on how to use the exercises, both with Binder and locally.
• Clear guidelines for contributing to the project.
• A credits section to acknowledge the original author.

[Windyskys]

update by jules

[rougier]

Thanks. I've added a comment on the credits. Also, your PR seems to have conflict.