Soyuz should store package uploader and approval details

Via sabdfl:
I could not find where we are recording the person who uploaded a package to a distro series. Of course we have details on SourcePackageRelease but remember that a release blob might get pushed into multiple distros. For example, say we have Gina sync of Debian unstable in LP, and someone does a native source sync "uploading" a package from there to Ubuntu. I would expect to see a PackageUpload record which tells us who did it, and when. If this resulted in a NEW package in Ubuntu, then we would also want that record to tell us who reviewed and approved that package, and when they did that. In the case of an "automatic" upload, by a script for example when a new series is opened and packages are copied in from the old to the new series, the uploader would be NULL but we might want to try and record where it came from (i.e. to Feisty from Edgy).