

**Description**

We are using a 3rd party executor which has the ability to use multiple queues, however the `default_queue` is defined under the `celery` heading and is used regardless of the executor that you are using.

See: https://github.com/apache/airflow/blob/2.0.1/airflow/models/baseoperator.py#L366

It would be nice to decouple the default_queue configuration argument away from the celery section to allow other executors to utilise this functionality with less confusion.

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

Yep! Will open a pull request shortly


**Related Issues**

Not that I'm aware of.

airflow/cli/cli_parser.py
"If you want to create a DOT file then you should execute the following command:\n"
            "airflow dags show <DAG_ID> --save output.dot\n"
        ),
        func=lazy_load_command('airflow.cli.commands.dag_command.dag_show'),
        args=(
            ARG_DAG_ID,
            ARG_SUBDIR,
            ARG_SAVE,
            ARG_IMGCAT,
        ),
    ),
    ActionCommand(
        name='backfill',
        help="Run subsections of a DAG for a specified date range",
        description=(
            "Run subsections of a DAG for a specified date range. If reset_dag_run option is used, "
            "backfill will first prompt users whether airflow should clear all the previous dag_run and "
            "task_instances within the backfill date range. If rerun_failed_tasks is used, backfill "
            "will auto re-run the previous failed task instances  within the backfill date range"
        ),
        func=lazy_load_command('airflow.cli.commands.dag_command.dag_backfill'),
        args=(
            ARG_DAG_ID,
            ARG_TASK_REGEX,
            ARG_START_DATE,
            ARG_END_DATE,
            ARG_MARK_SUCCESS,
            ARG_LOCAL,
            ARG_DONOT_PICKLE,
            ARG_YES,