[ENH] Upload status <> human readable

[rksh]

taking some feedback from previous code review, only to find a bug that needed fixing

• Upload status now uses an enum.
• Previous upload list row behavior hinged on human-readable strings, which was... broken.
• Not sure if there's a more elegant way to translate to human readable but at least this isn't broken.

[rksh]

we could move the IDs of the strings in there, but we'd still need a way to populate the translated strings outside the model object (otherwise we're passing Context into either the constructor or the getter to get the results in the right language for the users). Felt like weird trade-off, but I could be convinced to add the R.strings. values in as a second element to the Enum members if you think it's worthwhile/

[bobzilladev]

blah, yeah that's pry too weird a task for the enum to be taking on.