Harmonization of the way we are computing sliding_rp_violations

[yger]

After optimizing all metrics, I realized a slight discrepancies in sliding_rp_violations compared with our way of computing cross-correlograms. This has to do with several things, I think it would be worth harmonizing everything

• window_size_s in sliding_rp_violations is half the entire duration of the cross-correlograms, while in compute_correlograms, we assumed that window_size_s is the entire duration. There is thus here a factor 2 that could be misleading
• in compute_correlograms, we have a built-in mecanism to ensure the numbers of bins is odd, to avoid having an ambiguity at 0 with a bin -t, t that would not be properly symmetric. This is also not the case in sliding_rp_violations, that computes the number of bins in its own way, I guess less strict and precise.
  This PR uses compute_correlograms instead to solve the problem, but this would slightly change the results of the metrics. Who implemented that? Is it a feature, or should it be harmonized?