Extend the `import_from_postgis` function to import the buildings too
The current version does not import the buildings, but only tiles, entities and exposure data for the entities. It would be good to add the buildings as an option so that a complete dataset can be imported. This could be limited to the import of the final exposure data, so that buildings are not added to baseline exposure data imports. But this could also remain a user's choice to make things more simple for the code.