Bug 23721: Use basketgroup's name to name the CSV export file

Bug 23721: Use basketgroup's name to name the CSV export file

When exporting a basket group, the names of the files are different:
 * pdf => aqbasketgroup.name(.pdf)
 * csv => aqbasketgroup.id(.csv)

Better to use basketgroup's name for consistency and readability

Test plan:
Create a basketgroup and export it in pdf and CSV. The name of the
generated file must be the basketgroup's name suffixed by the extension.

Signed-off-by: Séverine QUEUNE <severine.queune@bulac.fr>
Signed-off-by: Marcel de Rooy <m.de.rooy@rijksmuseum.nl>
Signed-off-by: Martin Renvoize <martin.renvoize@ptfs-europe.com>