Change export of CC
cc.export() method must create a zipped folder including the minimum files needed to run fully a cc_protocol with a user's dataset: 1. full: all sign0 (.h5 files + fit.ready file in models folder) 2. reference: sign1 models folder (.pkl files only) --> sign1 are going to be generated based on sign0 at the initialization of the ChemicalChecker instance 3. reference: sign2 models (savedmodel folder only) --> sign2 are going to be generated based on sign1 and neig1 (also generated once sign1 is ready)