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.

return redirect_or_json(origin, msg, status="error", status_code=400)
        latest_execution_date = dag.get_latest_execution_date()
        if not latest_execution_date:
            msg = f"Cannot mark tasks as {state}, seem that dag {dag_id} has never run"
            return redirect_or_json(origin, msg, status="error", status_code=400)
        tasks: list[Operator | tuple[Operator, int]] = []
        if group_id:
            task_group_dict = dag.task_group.get_task_group_dict()
            task_group = task_group_dict.get(group_id)
            if task_group is None:
                return redirect_or_json(
                    origin, msg=f"TaskGroup {group_id} could not be found", status="error", status_code=404
                )
            tasks = [task for task in task_group.iter_tasks()]
        elif task_id:
            try:
                task = dag.get_task(task_id)
            except airflow.exceptions.TaskNotFound:
                msg = f"Task {task_id} not found"
                return redirect_or_json(origin, msg, status="error", status_code=404)
            task.dag = dag
            if map_indexes is None:
                tasks = [task]
            else:
                tasks = [(task, map_index) for map_index in map_indexes]
        to_be_altered = set_state(
            tasks=tasks,
            run_id=dag_run_id,
            upstream=upstream,
            downstream=downstream,