Visible Classes are useful, but lack a complete description in-game, which makes some of them trickier to understand than expected.
In particular, this is true of "Worker" right now (see D3290).
It's also annoying to maintain the list in Identity.js in my opinion, but that's neither here nor there.
This moves data to a .json file, inspired by status effects (almost a copy in fact -> should we have a generic tool?)
This is WIP, my plan would be to show the classes description when clicked on/hovered, à-la civopedia.
However, because the template viewer is just the tooltips, this is currently impossible.
I think we need a complete refactoring of these files, but that must come later.
If people agree with the direction, I'll move forward.