Fix ruff errors

[milton-minervino]

Description

This PR deals with ruff linting errors. Originally, ruff check returns several errors. We solve them by refactoring all the necessary code.
Furthermore, we refactor and fix code to get rid of many ruff lint exceptions listed under [tool.ruff.lint.per-file-ignores] in pyproject.toml.

Fixes #587

Type of change

• Bug fix (non-breaking change which fixes an issue)

How Has This Been Tested?

Pass all unit tests with pytest.

ruff check returns All checks passed!

Test Configuration:

• OS: Linux (Ubuntu)
• Python version: 3.12.3
• Shapash version: 2.9.0

Checklist:

• My code follows the style guidelines of this project
• I have performed a self-review of my own code
• I have commented my code, particularly in hard-to-understand areas
• I have made corresponding changes to the documentation
• My changes generate no new warnings
• I have added tests that prove my fix is effective or that my feature works
• New and existing unit tests pass locally with my changes
• Any dependent changes have been merged and published in downstream modules