[refactor] refactor main fitting function: by default, we fit without starting value, then we try several time with the start value

[quantile regression project]  fix bugs in daily_observations.py for the creation of the coordinates for the daily fit. some fix to prepare for some potential non stationary exponential model one day

[quantile regression project] add annual maxima osbervation from daily exponential. add sammple_r_function as argument to rmargin_from_nb_obs. add abstract extreme params

[EUROCODE][DRAWING PER REGION] modify test region eurocode. add test_ gev temporal bayesian. add stationary version for the Bayesian. refactor utils at the root, to root_uils to avoid weird import issues.

[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.

[MAX STABLE] add starting point for non stationary full estimator. fix display in non stationary trends

[EXTREME ESTIMATOR][MARGIN MODEL] add ismev gev fit. and refactor. add result_from_fit abstract class.

[EXTREME ESTIMATOR][MARGIN MODEL] add stationary/non-stationary margin model. fix margin formula (in the temporal case when we want a dependency on a single parameter for instance). add margin function with starting point