Allow building modules locally without fedmsg-hub.
    
    We started using `events.scheduler` to plan fake events instead of internal
    queue implemented by fedmsg-hub. Thanks to that, we can stop using fedmsg-hub
    completely for local builds.
    
    In this commit, the `scheduler.local.main` is rewritten to not use fedmsg-hub.
    The original `scheduler.local.main` is still needed by test_build tests and
    therefore it is moved there.