Restore git attribution string on user profile

As part of #2295411: Auto-generate Git attribution info / commit messages on Drupal.org the git attribution string has been removed from the user profiles, in commit d5bd108.

The reasoning behind this probably was that this was no longer needed since you can now generate the full commit string in the issue queue.

However I really miss having this information readily available. Not all work is strictly done through the issue queue. I am now busy porting modules to D8 and a lot of the grunt work is done without having a specific issue for every little step that needs to be done. I am also migrating code from a port that was published on Github but still want to properly attribute the original authors.

I now have to mock generate commit messages through an issue that was posted by the person I want to credit, just to be able to see the email address used for the git attribution. It would be much more interesting to have this information available on the user profile.