Investigate migration of Alioth Tracker items

We have a large number of Tracker Bug and Feature items over at Alioth. Many of these are still open, many are unassigned and many are pretty darn old. It is not clear whether it is feasible to migrate those. What is known is that Alioth's CSV export functionality is not very useful. It only provides the original submission without any attachments. That means it looses patches, logs and follow up comments.