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

[COORDINATE] refactor starting year & df_temporal_coordinates. to normalize the same way any temporal covariate. So that each fit has the same type of normalized data as input. add multiple transformation.

[EXTREME ESTIMATOR][MARGIN MODEL] add temporal linear margin model test. check that starting point are taken into account.

[EXTREME ESTIMATOR] add margin_fits folder. add gpd params & gpdmle_fit. refactor code to handle gev and gpd together

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