Generate Penpot file

[vanillajonathan]

Generate a Penpot file for use with Penpot.

These files are contributed to the penpot-files repository:
https://github.com/penpot/penpot-files

Issue:
penpot/penpot-files#13

[TravisSpomer]

Hi Jonathan! There's an upcoming W3C standard format for design tokens and we're planning on publishing our tokens for Fluent in that format. That's the token JSON format that everyone's rallying around so it seems certain that Penpot would support it in an upcoming version too!