Switch to content-addressible storage?

[PeterJCLaw]

Since we're really only storing one thing, it's not really required that we put it in a database.
We could for example move to storing the zip files on disk a bit like this:

archives
└── <tla>
    └── <sha25sum>.zip

We'd still need to serve the files ourselves in order to enforce our auth requirements, but this might be simpler to work with.

A downsides here is that adding metadata gets tricky. For example it's now a bit more effort to work out which was the most recent upload - we either rely on filesystem timestamps (fine, but may not have the nicest API) or munge it into the file names too.

[PeterJCLaw]

Even if we don't change to using filesystem storage, it may still be useful to move the pks of the database rows to being a content id rather than an incrementing number.