Add functionality to build a MapObject list from JSON for DHIS 2 Academy

For the prototype, we will not get the data directly from DHIS; instead, we will add functionality to build lists of map objects from JSON currently provided as-is by the DHIS current getGeoJson and getMapIndicatorValue.

Implement interval functionality for DHIS 2 Academy

The MapObject objects that we will use to draw to the map, should be categorized into different intervals. This functionality needs to be implemented alongside the MapObject class.