[contrasting project] add test for study loader. refactor their init function to have a better error message.

[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

[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