

**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/configuration.py
from cryptography.fernet import Fernet
            log.info('Creating new Airflow config file in: %s', AIRFLOW_CONFIG)
            pathlib.Path(AIRFLOW_HOME).mkdir(parents=True, exist_ok=True)
            FERNET_KEY = Fernet.generate_key().decode()
            with open(AIRFLOW_CONFIG, 'w') as file:
                file.write(default_config)
        log.info("Reading the config from %s", AIRFLOW_CONFIG)
        conf.read(AIRFLOW_CONFIG)
        if conf.has_option('core', 'AIRFLOW_HOME'):
            msg = (
                'Specifying both AIRFLOW_HOME environment variable and airflow_home '
                'in the config file is deprecated. Please use only the AIRFLOW_HOME '
                'environment variable and remove the config file entry.'
            )
            if 'AIRFLOW_HOME' in os.environ:
                warnings.warn(msg, category=DeprecationWarning)
            elif conf.get('core', 'airflow_home') == AIRFLOW_HOME:
                warnings.warn(
                    'Specifying airflow_home in the config file is deprecated. As you '
                    'have left it at the default value you should remove the setting '
                    'from your airflow.cfg and suffer no change in behaviour.',
                    category=DeprecationWarning,
                )
            else:
                AIRFLOW_HOME = conf.get('core', 'airflow_home')
                warnings.warn(msg, category=DeprecationWarning)
        
        
        if conf.getboolean('core', 'unit_test_mode'):
            conf.load_test_config()