Documentation should point to GitHub, not BitBucket anymore
Steps to reproduce
Steps to reproduce:
1. Even when looking at the front page of docs.opencast.org already, you see a link to BitBucket in the section titled "Development" under the heading "Code" and I found at least one other mention in the developer guide, too.
Following these links takes you to the Opencast BitBucket repository.
They should point to the brand spankin' new GitHub page!