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.

)
        num_logs = 0
        if ti is not None:
            num_logs = wwwutils.get_try_count(ti._try_number, ti.state)
        logs = [""] * num_logs
        root = request.args.get("root", "")
        return self.render_template(
            "airflow/ti_log.html",
            logs=logs,
            dag=dag_model,
            title="Log by attempts",
            dag_id=dag_id,
            task_id=task_id,
            execution_date=execution_date,
            map_index=map_index,
            form=form,
            root=root,
            wrapped=conf.getboolean("webserver", "default_wrap"),
        )
    @expose("/redirect_to_external_log")
    @auth.has_access(
        [
            (permissions.ACTION_CAN_READ, permissions.RESOURCE_DAG),
            (permissions.ACTION_CAN_READ, permissions.RESOURCE_TASK_INSTANCE),
            (permissions.ACTION_CAN_READ, permissions.RESOURCE_TASK_LOG),
        ]
    )
    @action_logging
    @provide_session
    def redirect_to_external_log(self, session: Session = NEW_SESSION):