Additions to the documentation and the testing

[sbaldu]

List of changes:

• Updated and extended the documentation of the library in the README file. Now the doc contains a more thorough description of the entire library and all its methods
• Additions to the tests of the Python code (both for local testing and CI/CD)
• Additions to the testing datasets (both for local testing and CI/CD)
• Better error handling on the Python side
• Better use of numpy in the Python code for improved performance and readability