### Body

There are some use cases where users want to trigger new DAG run as soon as one finished. This is a request I've seen several times with some variations (for example like this [Stackoverflow question](https://stackoverflow.com/q/75623153/14624409)) but the basic request is the same.

The workaround users do to get such functionality is place `TriggerDagRunOperator` as last task of their DAG invoking the same DAG:

```
from datetime import datetime

from airflow import DAG
from airflow.operators.empty import EmptyOperator
from airflow.operators.trigger_dagrun import TriggerDagRunOperator

with DAG(
    dag_id="example",
    start_date=datetime(2023, 1, 1,),
    catchup=False,
    schedule=None,
) as dag:
    task = EmptyOperator(task_id="first")
    trigger = TriggerDagRunOperator(
        task_id="trigger",
        trigger_dag_id="example",
    )

    task >> trigger

```

As you can see this works nicely:
![Screenshot 2023-03-03 at 14 20 51](https://user-images.githubusercontent.com/45845474/222718862-dfde8a41-24b6-4991-b318-b7f9784514f6.png)

My suggestion is to add first class support for this use case, so the above example will be changed to:

```

from datetime import datetime

from airflow import DAG
from airflow.operators.empty import EmptyOperator
from airflow.operators.trigger_dagrun import TriggerDagRunOperator

with DAG(
    dag_id="example",
    start_date=datetime(2023, 1, 1,),
    catchup=False,
    schedule="@continues",
) as dag:
    task = EmptyOperator(task_id="first")
```

I guess it won't exactly be `"@continues"` but more likely new [ScheduleArg](https://github.com/apache/airflow/blob/8b8552f5c4111fe0732067d7af06aa5285498a79/airflow/models/dag.py#L127) type but I show it like that just for simplification of the idea.

### Committer

- [X] I acknowledge that I am a maintainer/committer of the Apache Airflow project.
"""
            Create a subdag.
            """
            dag_subdag = DAG(
                dag_id=f"{parent_dag_name}.{child_dag_name}",
                schedule="@daily",
                default_args=args,
            )
            for i in range(2):
                EmptyOperator(task_id=f"{child_dag_name}-task-{i + 1}", dag=dag_subdag)
            return dag_subdag
        with DAG(
            dag_id="test_subdag_operator",
            start_date=datetime.datetime(2019, 1, 1),
            max_active_runs=1,
            schedule=timedelta(minutes=1),
        ) as dag:
            section_1 = SubDagOperator(
                task_id="section-1",
                subdag=subdag(dag.dag_id, "section-1", {"start_date": dag.start_date}),
            )
        subdag = section_1.subdag
        
        subdag.parent_dag = dag
        next_parent_info = dag.next_dagrun_info(None)
        assert next_parent_info.logical_date == timezone.datetime(2019, 1, 1, 0, 0)
        next_subdag_info = subdag.next_dagrun_info(None)
        assert next_subdag_info is None, "SubDags should never have DagRuns created by the scheduler"
    def test_replace_outdated_access_control_actions(self):