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.

.all()
        )
        recent_confs = {}
        for run in recent_runs:
            recent_conf = getattr(run, "conf")
            if isinstance(recent_conf, dict) and any(recent_conf):
                recent_confs[getattr(run, "run_id")] = json.dumps(recent_conf)
        if request.method == "GET":
            
            default_conf = ""
            doc_md = wwwutils.wrapped_markdown(getattr(dag, "doc_md", None))
            form = DateTimeForm(data={"execution_date": request_execution_date})
            if request_conf:
                default_conf = request_conf
            else:
                try:
                    default_conf = json.dumps(
                        {str(k): v.resolve(suppress_exception=True) for k, v in dag.params.items()},
                        indent=4,
                        ensure_ascii=False,
                    )
                except TypeError:
                    flash("Could not pre-populate conf field due to non-JSON-serializable data-types")
            return self.render_template(
                "airflow/trigger.html",
                form_fields=form_fields,
                dag_id=dag_id,
                origin=origin,
                conf=default_conf,
                doc_md=doc_md,