It allows to run LIS on SEN2COR Level 2A products. It will allow comparaison
between LIS.  This commit add:

- The detection of sen2cor product in the build_json script and default settings
(bands name, path...). Note that the parameter 'mode=sen2cor' is mandatory in
the json configuration. It is automaticcaly added by the build_json script

- Support for sen2cor in the LIS processor. The only difference is the way that
the cloud mask layers are extracted. Clouds and shadow layers are extracted from
the SCL sen2cor layer (scene classification)