GPII-103: Removal of 'datatype' from settings to options

Should be reviewed with: https://github.com/GPII/universal/pull/231

Changes:
* Registry settingshandler now expects the datatype to be passed in the options block instead of with individual preferences
* Added license header to test file + linted all files
* slightly changed the return payload of the "set" functionality to better match the rest of the framework. So we now get this:
 
        "Invert": {
            "oldValue": 0,
             "statusCode": 200,
            "newValue": 1
        }

Instead of the old way, with the unused bytes and statuscode for individual gets

         "Invert": {
            "oldValue": {
                "statusCode": 200,
                "bytes": 4,
                "value": 0
            },
            "statusCode": 200,
            "newValue": {
                "statusCode": 200,
                "bytes": 4,
                "value": 1
            }
        }