Avoid redundant GeoJSONs for multiple levels of government department

[Vonter]

For government departments that have a hierarchy with multiple levels, such as BBMP (Ward and Zone), separate GeoJSONs are used for the BBMP Ward and BBMP Zone. By storing the Zone metadata within the Ward polygon, the requirement of needing separate GeoJSONs can be avoided. The same optimization could be applied for BWSSB and BESCOM.

The end goal is to reduce the size of the boundaries.json, and potentially, officials.json.