frontend: pagure-events fedora messaging support
    
    Adds support for listening pagure-events on fedora-messaging
    and removes old zmq message bus.
    
    It's necessary to update .toml file where log_config.handles.console
    should look like this:
    
    [log_config.handlers.console]
    class = "logging.FileHandler"
    formatter = "simple"
    filename = "/var/log/copr-frontend/pagure-events.log"
    
    [[bindings]]
    queue = "00000000-0000-0000-0000-000000000003"
    exchange = "amq.topic"
    routing_keys = [
    'io.pagure.prod.pagure.git.receive',
    'io.pagure.prod.pagure.pull-request.new',
    'io.pagure.prod.pagure.pull-request.rebased',
    'io.pagure.prod.pagure.pull-request.updated',
    'io.pagure.prod.pagure.pull-request.comment.added',
    'org.fedoraproject.prod.pagure.git.receive',
    'org.fedoraproject.prod.pagure.pull-request.new',
    'org.fedoraproject.prod.pagure.pull-request.rebased',
    'org.fedoraproject.prod.pagure.pull-request.updated',
    'org.fedoraproject.prod.pagure.pull-request.comment.added',
    'io.pagure.stg.pagure.git.receive',
    'io.pagure.stg.pagure.pull-request.new',
    'io.pagure.stg.pagure.pull-request.rebased',
    'io.pagure.stg.pagure.pull-request.updated',
    'io.pagure.stg.pagure.pull-request.comment.added'
    ]
    
    Merges: #1025