Fixed mixed timestep when cmorizing atmosphere from grib_files. Started preparation of launcher and installation

Refactored data_manager to avoid a problem arising when variables have different number of levels. Added test.py to run unit tests with coveraga report

Created a class to encapsulate al the experiment management (get chunk list, get member str...) functionalities

Minor changes to make the diagnostics more user-friendly. Removed old diagnostics. Added measurement of time consumed by each diagnostic class