Random spike selection new methods

[tayheau]

So following #4251, a PR with a few new sampling methods for random_spikes_selection :

• percentage cap
• maximum_rate cap
• temporal_bins sampling for a better temporal representation of the original population, i tried to fully vectorize it so the temporal bin sampling problem is dual with a subsorting problem.

I also added to possibility to get_segment_durations to set segment_indices to None.