Sticker request: head-brain

[levimcg]

This came in as a request for marketing project that is in progress. Jenn has created a one-off version for now (screenshot attached), but this would make a nice addition to the library. We may want to wait a bit to see if any more requests come in the in the next month or so that way we can gang up new sticker additions in a release, but if someone has the time to work on this, go for it. Jenn can provide the final, optimized SVG.