[refactor] remove scores. remove non_stationary_trends, delete univariate_test_results that was deprecated

[paper 1] add plot for the presentation. increase the size of the legend for uncertainty curves. add sample function for the GevParams class.

[paper 1] modify the source of data (use the last version from AERIS) and shift the year being used (now study go from 1959 to 2019)

[paper 2] rename safran precipitation total to safran precipitation. add snowfall, precipitation, and rainfall study classes for 1, 3, 5 and 7 days

[paper 1] add plot with the difference in return level (and relative difference) for the big shapes. we conclude that there is big difference indeed

[paper 1] put by default the fact of discarding shape parameters that are not in the shape support. improve selection curve plot