Json Generator usage with curl generator and all concrete configuration models

[cgourdin]

Hello,

Adding a json generator will be an added value to perform occi task on runtime (MartServer and others).
First step : migrate json part from MartServer to OCCI core (studio), in MartServer, json objects will be used from occi core dependency.
Second step : add a new json generator project to OCCI-Studio to perform curl operations with json format.
Third step : Add a feature to import OCCI json and create automatically the configuration model.