generate, name, and export 20/16/12 icons separately

[felicio]

what

I thought we could generate just the largest subset and use SVG properties for scaling, but instead, we will have to generate, name, and export 20/16/12 separately.

– https://discord.com/channels/@me/1061951824342560808/1143828063960977461

why

• diff looking icons in size 12 altogether (e.g. communities)
• diff looking icons in size 12 altogether but same name (e.g. warning)
• thicker icon lines (e.g. info)
• diff name structure (e.g. 20/send/audio, 20/audio, 20/add, 20/emoji/faces)

where

• https://www.figma.com/file/qLLuMLfpGxK9OfpIavwsmK/Iconset?type=design&node-id=1-413&mode=design&t=ACTa0UhnjgGDwq3Q-0