Changes

Clinica Core:

[CI] Improve Jenkins configuration (Automatic generation of testing reports in order to be displayed in the CI interface; Recreate Python environment if requirements.txt changes)

[New] deeplearning-prepare-data pipeline: Prepare input data for deep learning with PyTorch. More info on the Wiki: http://www.clinica.run/doc/Pipelines/DeepLearning_PrepareData/
[Change] t1-linear pipeline now crops image on default. If --uncropped_image is added to the command line, the image is not cropped.
[Change] Refactor machine learning modules. Main changes involve use of CamelCase convention for classes and parameters used dictionaries.