OO-3797: Change default userid to email instead of username

src/main/resources/serviceconfig/olat.properties

@@ -1448,7 +1448,7 @@ edusharing.host=
 edusharing.ticket.valid.seconds=10
 
 # User attribute to pass as userid to edu-sharing
-edusharing.user.identifier.key=username
+edusharing.user.identifier.key=email
 edusharing.user.identifier.key.values=username,email
 
 # Names of user attributes are configurable in edu-sharing. Use the same names here.