[SCM][HYPERCUBE] improve labelling of all the graphs. add test strength display in the spatial case.

[SCM][HYPERCUBE] normalize gev trend_strength with distance between years. update test to check this distance.

[SCM][HYPERCUBE] Add possibility to create altitude hypercube effortlessly from quantity altitude hypercube (with an additional argument called add_detailed_plot)

[SCM][HYPERCUBE] Add visualization of trend with respect to the starting years. some refactoring and code factorization.

[SCM][HYPERCUBE] Add multiprocessing by default for abstract study. re-activate test_SCM_study which are now fast enough. fix issue with total precipitation variable. AltitudeHypercubeVisualizer first visualization.

[SCM][HYPERCUBE] Add multiprocessing when loading abstract study. Refactor abstract variable and all variables accordinlgly.

[SCM][HYPERCUBE] Create Hypercube object with MultiIndex. Modify @cached_property in utils (from a library and seems to a bit faster). added some parallelization for trend test type in study_visualizer.

[SCM][NON STATIONARY TREND] modify some display parameter. add pre loaded LATITUDE & LONGITUDE to scm_constants file. remove massif file.

[EXTREME ESTIMATOR] add max iteration argument for any R fit. also add some verbose for trend tests experiments.

[COORDINATES] add some normalization class for the coordinate, add a normalization function for the observations.

[COORDINATES] add one test to test_transformation. add some copying during coordinate transformation.