Move GeoExporter to use the standalone GeoModelIO from AthenaExternals.
The GeoExporter package is used by the DumpGeo Athena algorithm to dump the GeoModel tree to a local SQLite file.
Until now, it still used the old version of theGeoWrite package, the one still hosted under Athena for back-compatibility.
The GeoWrite package has been replaced by the GeoModelWrite package hosted under the standalone GeoModelIO package.
This MR move the GeoExporter package to use the AthenaExternals/GeoModelIO package instead of the old GeoWrite. It also removes the old packages from Athena (they have been replaced by packages in the standalone GeoModel).
Edited by Riccardo Maria Bianchi