Use geocoded AOI name for uploaded AOIs

When uploading AOI GeoJSON, the uploaded filename is used as the AOI name. If this is descriptive I could see how this would be an advantage, but if the filename is map.geojson, it is not useful. We should consider:
1. Informing users that the filename is the AOI name, and/or
2. Geocoding the area of the uploaded AOI to create a new AOI name
3. Allowing users to select either the uploaded filename or a geocoded AOI name

Start at the GeoJSON upload flow and trace where the uploaded filename becomes the AOI name. Compare the three naming options in the issue and determine whether an existing geocoding entry point is available. Done requires an agreed naming behavior and a clear description of how users choose or receive the AOI name.

Written by the indexing model from the issue text.