

**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_PORT,
            ARG_WORKERS,
            ARG_WORKERCLASS,
            ARG_WORKER_TIMEOUT,
            ARG_HOSTNAME,
            ARG_PID,
            ARG_DAEMON,
            ARG_STDOUT,
            ARG_STDERR,
            ARG_ACCESS_LOGFILE,
            ARG_ERROR_LOGFILE,
            ARG_ACCESS_LOGFORMAT,
            ARG_LOG_FILE,
            ARG_SSL_CERT,
            ARG_SSL_KEY,
            ARG_DEBUG,
        ),
    ),
    ActionCommand(
        name='scheduler',
        help="Start a scheduler instance",
        func=lazy_load_command('airflow.cli.commands.scheduler_command.scheduler'),
        args=(
            ARG_SUBDIR,
            ARG_NUM_RUNS,
            ARG_DO_PICKLE,
            ARG_PID,
            ARG_DAEMON,
            ARG_STDOUT,
            ARG_STDERR,