[new] graphics/peek, a simple screencast to mp4/gif recorder

Hi,

seems to work in basic testing, either outputting gif or mp4 files, cf
https://github.com/phw/peek/ for the website. it can use
https://gif.ski/ at runtime if found but that isnt port yet, for now it
seems to work fine using ffmpeg. Note: this doesnt record audio, only
the screen :)

feedback welcome !

Landry