new commands: create-test-data and remove-test-data
    
    These new commands allow to create example data (milestones, bugs, updates)
    under a release with number 101. This is mostly useful for development, but I
    thought it might be a good idea to make it generally available instead of just
    to developers. With this data, it's easy to explore most functionality of
    BlockerBugs and see how different pages and widgets look like.
    
    Merges: https://pagure.io/fedora-qa/blockerbugs/pull-request/203