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

[POSTER EVAN] improve visualization of the starting years for the poster. some refactorign for the Alps graph and cmap, from now on, we will only remove the last 20 starting years

[SCM] improve visualization of the margin. add a 2D optional mask & visualization bounds to visualize a 2D margin

[EXTREME PARAMETERS] create an attribute undefined_parameters in ExtremeParameters object, to avoid crash when a shape is < 0 for point while we want to display