**Description**

It would be great having a option to abort a DAG Runs through the REST API.

**Use case / motivation**

The proposed input params would be:
 - DAG_ID
 - DAG_RUN_ID

The DAG Run should abort all its tasks running and mark them as "failed".

**Are you willing to submit a PR?**

**Related Issues**


tests/api_connexion/endpoints/test_dag_run_endpoint.py
self._create_dag_runs(200)
        response = self.client.post(
            "api/v1/dags/~/dagRuns/list", json={}, environ_overrides={'REMOTE_USER': "test"}
        )
        assert response.status_code == 200
        assert response.json["total_entries"] == 200
        assert len(response.json["dag_runs"]) == 100  
    def _create_dag_runs(self, count):
        dag_runs = [
            DagRun(
                dag_id="TEST_DAG_ID",
                run_id="TEST_DAG_RUN_ID" + str(i),
                state='running',
                run_type=DagRunType.MANUAL,
                execution_date=timezone.parse(self.default_time) + timedelta(minutes=i),
                start_date=timezone.parse(self.default_time),
                external_trigger=True,
            )
            for i in range(1, count + 1)
        ]
        dag = DagModel(dag_id="TEST_DAG_ID")
        with create_session() as session:
            session.add_all(dag_runs)
            session.add(dag)
class TestGetDagRunBatchDateFilters(TestDagRunEndpoint):