Use configurable tezor data in models

aleksis/apps/paweljong/models.py

@@ -397,9 +397,9 @@ class EventRegistration(ExtensibleModel):
 
     def get_invoice(self):
         # FIXME Maybe do not hard-code this
-        client, __ = Client.objects.get_or_create(name="Teckids e.V.")
+        client, __ = Client.objects.get_or_create(name=get_site_preferences()["paweljong__event_invoice_client_name"])
         group, __ = InvoiceGroup.objects.get_or_create(
-            name="Hack'n'Fun-Veranstaltungen",
+            name=get_site_preferences()["paweljong__event_invoice_group_name"],
             client=client,
             defaults={
                 "template_name": "paweljong/invoice_pdf.html",