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.

"""Formats log URL."""
        log_url = self.get("log_url")
        return Markup(
            '<a href="{log_url}"><span class="material-icons" aria-hidden="true">reorder</span></a>'
        ).format(log_url=log_url)
    def duration_f(self):
        """Formats duration."""
        end_date = self.get("end_date")
        duration = self.get("duration")
        if end_date and duration:
            return td_format(datetime.timedelta(seconds=duration))
        return None
    formatters_columns = {
        "log_url": log_url_formatter,
        "task_id": wwwutils.task_instance_link,
        "run_id": wwwutils.dag_run_link,
        "map_index": wwwutils.format_map_index,
        "hostname": wwwutils.nobr_f("hostname"),
        "state": wwwutils.state_f,
        "dag_run.execution_date": wwwutils.datetime_f("dag_run.execution_date"),
        "start_date": wwwutils.datetime_f("start_date"),
        "end_date": wwwutils.datetime_f("end_date"),
        "queued_dttm": wwwutils.datetime_f("queued_dttm"),
        "dag_id": wwwutils.dag_link,
        "duration": duration_f,
    }
    @action(