

**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
path = _default_config_file_path('default_airflow.cfg')
    with open(path) as fh:
        return fh.read()
@functools.lru_cache(maxsize=None)
def _TEST_CONFIG():
    path = _default_config_file_path('default_test.cfg')
    with open(path) as fh:
        return fh.read()
_deprecated = {
    'DEFAULT_CONFIG': _DEFAULT_CONFIG,
    'TEST_CONFIG': _TEST_CONFIG,
    'TEST_CONFIG_FILE_PATH': functools.partial(_default_config_file_path, ('default_test.cfg')),
    'DEFAULT_CONFIG_FILE_PATH': functools.partial(_default_config_file_path, ('default_airflow.cfg')),
}
def __getattr__(name):
    if name in _deprecated:
        warnings.warn(
            f"{__name__}.{name} is deprecated and will be removed in future",
            DeprecationWarning,
            stacklevel=2,