Add variable font metadata

[itsdouges]

• adds axes.json which has variable font axes definitions
• adds axes to metadata.json
• updates s in fonts.json to include variants and axes if defined

we'll want to copy fonts.json, axis.json, and the updated font-chunk.avifs into paper, here are direct links:

• font-chunks
• fonts.json
• axes.json

[vladmoroz]

• We need axes min/default/max per font, as they vary. Not sure why Google stores global min/default/max for each axis.
• We can reduce the axes registry to an object "TAG": "Display name"
  • precision is nice but looks like we can drop it too since we don't have access to that with local fonts, so we'd need to implement a general-purpose heuristic to determine precision either way (font files don't carry this info)

[vladmoroz]

let's also sort the axes in the font metadata same way we are going to do it in the app

[itsdouges]

Ok will adjust