Cleanup of spatial zoning data structure
Currently, spatial zones at the country, municipal and quarter level are merged into a single dataframe and reassigned a new unique id. This was done in order split up cities like Zurich into its quarters while maintaining a flat zoning system for later assignments (for example STATENT enterprises). However, when dealing with NUTS and postal zones, there are now many overlapping zones. Maybe it simply makes sense to have this list of all zones of different types and then assign each point to a country, municipality, quarter, NUTS and postal code without being exclusive?