Refactored: gn-auth - client credentials are now sent within the header
Refactored: gn-constants/gn-endpoints/gn-sdk - each function now has two arguments: params and body.
The body is meant to be sent in the request body as usual, whereas the params will be mapped to url params as defined in gn-constants. If the param is not present in the url, it will be sent as a query string
Refactored: gn-endpoints - now Gerencianet endpoints are restfull, which means that the sdk must consider sending also put and delete