"Older versions" download links

[gonX]

I imagine it'll be implemented by having a json with an array of versions, each with a version name and their associated download links.

Not sure how it'll turn out visually - maybe a dropdown of versions and then show its associated download links?

[gonX]

Might be worth considering together with #302

Would be interesting to just pre-populate a JSON with direct links to the individual releases - this may be slightly more work to maintain, but the work is consistent, doesn't take too long, and doesn't lock us into having to use standardized asset names (as they haven't always been standardized)