Code refactor (ML)

[Sinclert]

This PR refactor the Python code for the Machine Learning use-case (docker-images-ml/code).

The refactor includes nice additions like:

• Relative paths: allowing scripts to be run locally (debug).
• Standarized code blocks: most scripts present a similar structure:
  • Definition of global variables.
  • Argument parsing.
  • Configuration loading.
  • Custom steps...
  • Saving a particular file.