Harvester should work for other cities

[JensWinter]

Currently the harvester only works for Berlin out of the box. To make use of the harvester for other cities, this repo has to be forked and modified. As this repo is designed as a Github action it would be great if it could be used for any city without having to create a fork.

I can see at least two approaches:

1. Add other cities shape files to the repo. The harvester will be run with a target city parameter. (Further shape files can be added via PRs)
2. Keep city shape files outside of the repo and load it from a remote location at runtime.

[JensWinter]

3. Use geojson file format as input instead of shp. The content of the file could be passed into the action from the calling workflow.

[ff6347]

I like 2. or even better 3. The geojson/shp file should be in the repo where the action is run and not in the action source repo itself.