

**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
default=conf.getint('scheduler', 'num_runs'),
    type=int,
    help="Set the number of runs to execute before exiting",
)
ARG_DO_PICKLE = Arg(
    ("-p", "--do-pickle"),
    default=False,
    help=(
        "Attempt to pickle the DAG object to send over "
        "to the workers, instead of letting workers run their version "
        "of the code"
    ),
    action="store_true",
)
ARG_QUEUES = Arg(
    ("-q", "--queues"),
    help="Comma delimited list of queues to serve",
    default=conf.get('celery', 'DEFAULT_QUEUE'),
)
ARG_CONCURRENCY = Arg(
    ("-c", "--concurrency"),
    type=int,
    help="The number of worker processes",
    default=conf.get('celery', 'worker_concurrency'),
)
ARG_CELERY_HOSTNAME = Arg(
    ("-H", "--celery-hostname"),
    help="Set the hostname of celery worker if you have multiple workers on a single machine",
)
ARG_UMASK = Arg(