Add a column to optionally associate stls with a badge.

This will be nice now that @hroncok has provided us with stls:
https://git.fedorahosted.org/cgit/badges.git/tree/stls

..and with a method to generate them:
https://git.fedorahosted.org/cgit/badges.git/tree/bin
Merge pull request #33 from fedora-infra/feature/stls

Add a column to optionally associate stls with a badge.