[contrasting project] add file that enable to reveal the snow partition for biggest snow load observed. refactor crocus files

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

[contrasting project] remove the restriction of maxima to winter. because i will focus only on snowfall so i don't really need that restriction

[contrasting project] generate plot for the trends in return levels for the winter extended. do the same for the distribution of wps. remove winter_maxima and summer_maxima in abstract_study.py

[contrasting project] add test_year_to_winter_date. add the possibility to select a season for in abstract_study.py