

**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
"""Historical getsection"""
    warnings.warn(
        "Accessing configuration method 'getsection' directly from the configuration module is "
        "deprecated. Please access the configuration from the 'configuration.conf' object via "
        "'conf.getsection'",
        DeprecationWarning,
        stacklevel=2,
    )
    return conf.getsection(*args, **kwargs)
def has_option(*args, **kwargs):  
    """Historical has_option"""
    warnings.warn(
        "Accessing configuration method 'has_option' directly from the configuration module is "
        "deprecated. Please access the configuration from the 'configuration.conf' object via "
        "'conf.has_option'",
        DeprecationWarning,
        stacklevel=2,
    )
    return conf.has_option(*args, **kwargs)
def remove_option(*args, **kwargs):  
    """Historical remove_option"""
    warnings.warn(
        "Accessing configuration method 'remove_option' directly from the configuration module is "
        "deprecated. Please access the configuration from the 'configuration.conf' object via "
        "'conf.remove_option'",
        DeprecationWarning,
        stacklevel=2,
    )
    return conf.remove_option(*args, **kwargs)
def as_dict(*args, **kwargs):