add source file for logo to repository

[afeld]

Assuming the source file was a vector illustration. The rasterized version:

https://github.com/opencontrol/website/blob/87a26de0e45826d4ef6f327308c8ef979ed36da2/img/oclogo.png

[afeld]

Sounds like it was made in an online generator, so there isn't one really. We should recreate as a vector. Font is Abel Pro.