Service layer model not implemented consistently

[ognjenkurtic]

Each of the services serves to fetch one of the variables used in the formula to calculate the emissions. Services depend on providers to fetch the actual data. A provide could be a JSON, API or something else. The responsibility of the provider should be to fetch the data, map it to it's own internal model and then translate the internal model to the service layer model used for the calculation. This should be consistently implemented across the app.