#22 Data restructure: Port per-album/thing data files

This isn't immediately blocking because these aren't actually used on the website (except for info cards, which are currently disabled and not yet finished being implemented), but they'd be nice to bring over too. And an easy demonstration of the new data format!

I don't think the actual structure (key names etc) of the data files should be changed now, but it's worth revisiting to make them pair more one-to-one with the refined property names on the new Thing classes.

Copy-paste from #54:

We can further investigate exposing data in more useful ways later, but for now, simply re-enabling the existing data generation (and double-checking that everything still works) would be a good first step, as long as it doesn't involve Too Much work.