Creation of contingencies in the CGMES tutorial

[agnesLeroy]

• Do you want to request a feature or report a bug?
  This is a suggestion for improvement in the CGMES tutorial.

• What is the current behavior?
  When creating the contingencies, there are three examples of how to do it in the tutorial.
  This seems confusing to me: why not show only recommended way of doing it ? The contingenciesProvider and contingenciesProvider1 could be removed.

• What is the motivation / use case for changing the behavior?
  The motivation would be to try and diffuse the state-of-the-art methodology through the tutorials.