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.

"""Form widget used to display connection."""
    @cached_property
    def field_behaviours(self) -> str:
        return json.dumps(ProvidersManager().field_behaviours)
    @cached_property
    def testable_connection_types(self) -> list[str]:
        return [
            connection_type
            for connection_type, hook_info in ProvidersManager().hooks.items()
            if hook_info and hook_info.connection_testable
        ]
class ConnectionFormProxy:
    """A stand-in for the connection form class.
    Flask-Appbuilder model views only ever call the ``refresh()`` function on
    the form class, so this is the perfect place to make the form generation
    dynamic. See docstring of ``create_connection_form_class`` for rationales.
    """
    @staticmethod
    def refresh(obj=None):
        return create_connection_form_class().refresh(obj)
class ConnectionModelView(AirflowModelView):