Disallow URL shorteners in commit messages/code

If a URL is mentioned in a commit message or in some code comment, it shouldn't be a shortened URL or one of a redirect service. If such a service goes down or disappears or the URL times out or whatever, we're left with absolutely no clue about what the link was pointing to.

Eg. see https://codereview.qt-project.org/c/qt/qtbase/+/341203

I'm not sure how to do this properly, but I guess a blacklist would suffice as a starter.