**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
@parameterized.expand(
        [
            ({"page_limit": 1}, ["TEST_DAG_RUN_ID1"]),
            ({"page_limit": 2}, ["TEST_DAG_RUN_ID1", "TEST_DAG_RUN_ID2"]),
            (
                {"page_offset": 5},
                [
                    "TEST_DAG_RUN_ID6",
                    "TEST_DAG_RUN_ID7",
                    "TEST_DAG_RUN_ID8",
                    "TEST_DAG_RUN_ID9",
                    "TEST_DAG_RUN_ID10",
                ],
            ),
            (
                {"page_offset": 0},
                [