[EXTREME ESTIMATOR] refactor margin_fits folder. extreme estimator folder. and extreme_models folder

[EXTREME ESTIMATOR][MARGIN MODEL] refactor linear margin model folder organization. refactor names in univariate trend analysis

[EXTREME ESTIMATOR][MAX STABLE] improve the exception error message when trying to sample with 3D coordinates and the wrong arguments

[EXTREME ESTIMATOR][MAX STABLE] add argument use_rmaxstab_with_2_coordinates to rmaxstab that makes it possible to sample dataset with 3D coordinates

[TEST][DATASET] major fix for abstract_dataset for the function transform_maxima in the spatio temporal case

[MAX STABLE MODEL] add fitmaxstab for 1D coordinates (by building 2D coordinates from the 1D coordinates)