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.

try_count = ti.prev_attempted_tries if ti.prev_attempted_tries != 0 else ti.try_number
            task_dict = alchemy_to_dict(ti) or {}
            task_dict["end_date"] = task_dict["end_date"] or timezone.utcnow()
            task_dict["extraLinks"] = dag.get_task(ti.task_id).extra_links
            task_dict["try_number"] = try_count
            task_dict["execution_date"] = dttm.isoformat()
            task_dict["run_id"] = dag_run_id
            tasks.append(task_dict)
        tf_count = 0
        try_count = 1
        prev_task_id = ""
        for failed_task_instance in ti_fails:
            if not dag.has_task(failed_task_instance.task_id):
                continue
            if tf_count != 0 and failed_task_instance.task_id == prev_task_id:
                try_count += 1
            else:
                try_count = 1
            prev_task_id = failed_task_instance.task_id
            tf_count += 1
            task = dag.get_task(failed_task_instance.task_id)
            task_dict = alchemy_to_dict(failed_task_instance) or {}
            end_date = task_dict["end_date"] or timezone.utcnow()
            task_dict["end_date"] = end_date
            task_dict["start_date"] = task_dict["start_date"] or end_date
            task_dict["state"] = State.FAILED
            task_dict["operator"] = task.operator_name
            task_dict["try_number"] = try_count
            task_dict["extraLinks"] = task.extra_links
            task_dict["execution_date"] = dttm.isoformat()