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.

if dt is None:
                        break
                    if dt.year != year:
                        break
                    if dag.end_date and dt > dag.end_date:
                        break
                    dates[dt.date()] += 1
            else:
                prev_logical_date = DateTime.min
                while True:
                    curr_info = dag.timetable.next_dagrun_info(
                        last_automated_data_interval=last_automated_data_interval,
                        restriction=restriction,
                    )
                    if curr_info is None:
                        break  
                    if curr_info.logical_date <= prev_logical_date:
                        break  
                    if curr_info.logical_date.year != year:
                        break  
                    last_automated_data_interval = curr_info.data_interval
                    dates[curr_info.logical_date] += 1
                    prev_logical_date = curr_info.logical_date
            data_dag_states.extend(
                {"date": date.isoformat(), "state": "planned", "count": count}
                for (date, count) in dates.items()
            )
        now = DateTime.utcnow()
        data = {
            "dag_states": data_dag_states,