Use gunicorn to run app
    
    This will switch using gunicorn instead of flask.run() for running the app.
    
    It also swtiches storing settings.py in a Secret instead of a ConfigMap
    in order to keep secret information under control.
    
    Template asks for image name instead of version, this way resultsdb image
    stored in an external registry can be also used.
    
    Note that this is not a production ready solution, as resultsdb
    requires authorization to be handled by the server. In current deployements
    this is done using httpd configuration, but I was not able to find
    a similar solution with gunicorn.