mite.watch for GitHub and GitLab

This is a simple one click extension: You can start a new mite tracker simply from any GitHub or GitLab issue page. You can also select a project and service for each repository if you like. That setting will be remembered for the next use. The default issue note contains the issue number, description and a link. Example: '#423 Refactor image uploader http://github.com/example/example/issues/123'