[contrasting] add code to retrieve gcm_rcm_couples. start code to compare bias on the quantile period (between projecitons, and ADAMONT 2020)

[contrasting] add gap between study. and add safran 2019 from max files. add main_comparison_histo.py

[snow projection] improve rank & bias plots. remove dataset attribute for abstract_adamont_study.py.

[snow projection] improve drastically the loading time for the abstract_adamont_study.py based on a simple conversion to numpy array.
 remove fit_method from plot_map argument.

add altitude argument to adamont studies. refactor a bit. add time series display for adamont series