Add export links to the website

[tordans]

Goal

https://parkraum.osm-verkehrswende.org/regions/berlin/ and all other regions should have export links.

TODOs

• [x] Update the website to use the new API from https://github.com/osmberlin/osm-parking-processing/issues/76 to list all active regions – @tordans
• [x] Update the website to list all available downloads based on the URL schema from that API – @tordans

[tordans]

Conclusion

Data sources are listed at https://parkraum.osm-verkehrswende.org/regions/berlin/ per region.

Website uses a new system to build based on the new regions-data source.

Follow up for documentation

See https://github.com/osmberlin/parkraum.osm-verkehrswende.org/issues/49