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.

run_id = None
                record = None
                def set_overall_state(record):
                    for state in wwwutils.priority:
                        if state in record["mapped_states"]:
                            record["state"] = state
                            break
                    if None in record["mapped_states"]:
                        
                        
                        record["mapped_states"]["no_status"] = record["mapped_states"].pop(None)
                for ti_summary in ti_summaries:
                    if run_id != ti_summary.run_id:
                        run_id = ti_summary.run_id
                        if record:
                            set_overall_state(record)
                            yield record
                        record = {
                            "task_id": ti_summary.task_id,
                            "run_id": run_id,
                            "start_date": ti_summary.start_date,
                            "end_date": ti_summary.end_date,
                            "mapped_states": {ti_summary.state: ti_summary.state_count},
                            "state": None,  
                        }
                        continue
                    record["start_date"] = min(
                        filter(None, [record["start_date"], ti_summary.start_date]), default=None