Created dark and light mode figures

• Changed some images so that dark mode looks better.
• Improve the doc/dev part of the documentation
• Fixed the new lint errors

Note : In theory, I should have been able to have a dark and a light logo, but for some reasons it does not work, so I went for a MAICoS text written in gray instead of white, at least it is visible on both dark and light modes, and it looks quite nice :

PR Checklist

• Docs?
• Issue raised/referenced? (no associated issue)