Fix live feedback for data upload (previously provided by the stats)
To fix performance issues the statistics page gets chached since !208 (merged).
When it was "realtime", it was used by uploaders to verify that frames were received and processed by the DB. Due to the caching this feedback isn't directly available anymore.
So I guess we need to fix this or find/create another feedback path for data uploader.
Maybe it is an idea to change the stats page. On the index page only show the last ten or twenty inserts.