

**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
ARG_FLOWER_URL_PREFIX = Arg(
    ("-u", "--url-prefix"), default=conf.get('celery', 'FLOWER_URL_PREFIX'), help="URL prefix for Flower"
)
ARG_FLOWER_BASIC_AUTH = Arg(
    ("-A", "--basic-auth"),
    default=conf.get('celery', 'FLOWER_BASIC_AUTH'),
    help=(
        "Securing Flower with Basic Authentication. "
        "Accepts user:password pairs separated by a comma. "
        "Example: flower_basic_auth = user1:password1,user2:password2"
    ),
)
ARG_TASK_PARAMS = Arg(("-t", "--task-params"), help="Sends a JSON params dict to the task")
ARG_POST_MORTEM = Arg(
    ("-m", "--post-mortem"), action="store_true", help="Open debugger on uncaught exception"
)
ARG_ENV_VARS = Arg(
    ("--env-vars",),
    help="Set env var in both parsing time and runtime for each of entry supplied in a JSON dict",
    type=json.loads,
)
# connections
ARG_CONN_ID = Arg(('conn_id',), help='Connection id, required to get/add/delete a connection', type=str)
ARG_CONN_ID_FILTER = Arg(
    ('--conn-id',), help='If passed, only items with the specified connection ID will be displayed', type=str
)
ARG_CONN_URI = Arg(
    ('--conn-uri',), help='Connection URI, required to add a connection without conn_type', type=str
)
ARG_CONN_TYPE = Arg(