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.

"""Multiple delete action."""
        self.datamodel.delete_all(items)
        self.update_redirect()
        return redirect(self.get_redirect())
    def pre_add(self, item):
        """Pre add hook."""
        item.execution_date = timezone.make_aware(item.execution_date)
        item.value = XCom.serialize_value(
            value=item.value,
            key=item.key,
            task_id=item.task_id,
            dag_id=item.dag_id,
            run_id=item.run_id,
            map_index=item.map_index,
        )
    def pre_update(self, item):
        """Pre update hook."""
        item.execution_date = timezone.make_aware(item.execution_date)
        item.value = XCom.serialize_value(
            value=item.value,
            key=item.key,
            task_id=item.task_id,
            dag_id=item.dag_id,
            run_id=item.run_id,
            map_index=item.map_index,
        )
#
#
class ConnectionFormWidget(FormWidget):