The DAGs main page has All/Active/Paused.

It would be nice if we can have also Running Now which will show all the DAGs that have at least 1 in Running of DAG runs:
![Screen Shot 2021-08-25 at 11 30 55](https://user-images.githubusercontent.com/62940116/130756490-647dc664-7528-4eb7-b4d8-515577f7e6bb.png)


For the above example the new DAGs tab of Running Now should show only 2 rows.
The use case is to see easily what DAGs are currently in progress.

"""Show Method Not Allowed on screen for any error in the Webserver."""
    return (
        render_template(
            "airflow/error.html",
            hostname=get_hostname() if conf.getboolean("webserver", "EXPOSE_HOSTNAME") else "redact",
            status_code=405,
            error_message="Received an invalid request.",
        ),
        405,
    )
def show_traceback(error):
    """Show Traceback for a given error."""
    return (
        render_template(
            "airflow/traceback.html",
            python_version=sys.version.split(" ")[0] if g.user.is_authenticated else "redact",
            airflow_version=version if g.user.is_authenticated else "redact",
            hostname=get_hostname()
            if conf.getboolean("webserver", "EXPOSE_HOSTNAME") and g.user.is_authenticated
            else "redact",
            info=traceback.format_exc()
            if conf.getboolean("webserver", "EXPOSE_STACKTRACE") and g.user.is_authenticated
            else "Error! Please contact server admin.",
        ),
        500,
    )
class AirflowBaseView(BaseView):