Function `_import_exposure()` should be changed to allow imports from SpatiaLite databases too
The new program globalmerge in the exposure-share repository requires to import entities, assets and taxonomy strings from many SpatiaLite databases. This functionality is basically provided in the _import_exposure() function. A simple solution would be to remove the restriction to a PostGISExposure object as source and rename the function to not being internal anymore.
Additionally, a new function should be added that get all unique Quadkeys from a SpatiaLite database because such a list is needed to run the _import_exposure() function.
Edited by Danijel Schorlemmer