Draft: json: create two static lib to serialize and deserialize input_item_t

This merge request is the first part of making the preparser running in a different process. Its purpose is to discuss and be sure that's the way to go.

This introduce de/serialization to and from json of the useful part input_item_t. The function's name and the two static lib structure are open to discussion and will perhaps be merge in one static library with all other de/serialization functions needed and not done yet.

Next step:

• preparser binary that receive preparse request and send responce.
• an API that spawn the preparser process and send preparse request.