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.

"max_active_runs": max_active_runs,
                }
            )
        return flask.json.jsonify(payload)
    def _mark_dagrun_state_as_failed(self, dag_id, dag_run_id, confirmed):
        if not dag_run_id:
            return {"status": "error", "message": "Invalid dag_run_id"}
        dag = get_airflow_app().dag_bag.get_dag(dag_id)
        if not dag:
            return {"status": "error", "message": f"Cannot find DAG: {dag_id}"}
        new_dag_state = set_dag_run_state_to_failed(dag=dag, run_id=dag_run_id, commit=confirmed)
        if confirmed:
            return {"status": "success", "message": f"Marked failed on {len(new_dag_state)} task instances"}
        else:
            details = [str(t) for t in new_dag_state]
            return htmlsafe_json_dumps(details, separators=(",", ":"))
    def _mark_dagrun_state_as_success(self, dag_id, dag_run_id, confirmed):
        if not dag_run_id:
            return {"status": "error", "message": "Invalid dag_run_id"}
        dag = get_airflow_app().dag_bag.get_dag(dag_id)
        if not dag:
            return {"status": "error", "message": f"Cannot find DAG: {dag_id}"}
        new_dag_state = set_dag_run_state_to_success(dag=dag, run_id=dag_run_id, commit=confirmed)
        if confirmed:
            return {"status": "success", "message": f"Marked success on {len(new_dag_state)} task instances"}
        else:
            details = [str(t) for t in new_dag_state]
            return htmlsafe_json_dumps(details, separators=(",", ":"))
    @provide_session
    def _mark_dagrun_state_as_queued(