

**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/config_templates/default_celery.py
DEFAULT_CELERY_CONFIG = {
    'accept_content': ['json'],
    'event_serializer': 'json',
    'worker_prefetch_multiplier': conf.getint('celery', 'worker_prefetch_multiplier', fallback=1),
    'task_acks_late': True,
    'task_default_queue': conf.get('celery', 'DEFAULT_QUEUE'),
    'task_default_exchange': conf.get('celery', 'DEFAULT_QUEUE'),
    'task_track_started': conf.get('celery', 'task_track_started', fallback=True),
    'broker_url': broker_url,
    'broker_transport_options': broker_transport_options,
    'result_backend': conf.get('celery', 'RESULT_BACKEND'),
    'worker_concurrency': conf.getint('celery', 'WORKER_CONCURRENCY'),
}
celery_ssl_active = False
try:
    celery_ssl_active = conf.getboolean('celery', 'SSL_ACTIVE')
except AirflowConfigException:
    log.warning("Celery Executor will run without SSL")
try:
    if celery_ssl_active:
        if 'amqp://' in broker_url:
            broker_use_ssl = {
                'keyfile': conf.get('celery', 'SSL_KEY'),
                'certfile': conf.get('celery', 'SSL_CERT'),
                'ca_certs': conf.get('celery', 'SSL_CACERT'),
                'cert_reqs': ssl.CERT_REQUIRED,
            }
        elif 'redis://' in broker_url:
            broker_use_ssl = {
                'ssl_keyfile': conf.get('celery', 'SSL_KEY'),