

**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 PNG file then you should execute the following command:\n"
            "airflow dags test <DAG_ID> <EXECUTION_DATE> --save-dagrun output.png\n"
            "\n"
            "If you want to create a DOT file then you should execute the following command:\n"
            "airflow dags test <DAG_ID> <EXECUTION_DATE> --save-dagrun output.dot\n"
        ),
        func=lazy_load_command('airflow.cli.commands.dag_command.dag_test'),
        args=(
            ARG_DAG_ID,
            ARG_EXECUTION_DATE,
            ARG_SUBDIR,
            ARG_SHOW_DAGRUN,
            ARG_IMGCAT_DAGRUN,
            ARG_SAVE_DAGRUN,
        ),
    ),
)
TASKS_COMMANDS = (
    ActionCommand(
        name='list',
        help="List the tasks within a DAG",
        func=lazy_load_command('airflow.cli.commands.task_command.task_list'),
        args=(ARG_DAG_ID, ARG_TREE, ARG_SUBDIR, ARG_VERBOSE),
    ),
    ActionCommand(
        name='clear',
        help="Clear a set of task instance, as if they never ran",
        func=lazy_load_command('airflow.cli.commands.task_command.task_clear'),
        args=(
            ARG_DAG_ID,