(feat) Image magic rounded avatars

Added a new v2/media/magicproxy endpoint Added a new image resizer that uses imagemagick The only change I had to make to the existing downloader was to allow me to get access to the stream because imagemagick hates gd image resources and I'd need to do some funky re-encoding. Just provided an intermediary downloadBinaryString which the pre-existing download calls

No unit tests because to do anything meaningful would require installing imagemagick which requires major tinkering to get working locally. Not to keen on breaking running tests locally just yet.

Hey, the composer SHA has changed and it breaks the installer. I changed the hash here and have created a card to add in downloading and comparing the hash