

**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
option = self._get_cmd_option(section, key)
        if option:
            return option
        if deprecated_section:
            option = self._get_cmd_option(deprecated_section, deprecated_key)
            if option:
                self._warn_deprecate(section, key, deprecated_section, deprecated_key)
                return option
        return None
    def _get_option_from_config_file(self, deprecated_key, deprecated_section, key, kwargs, section):
        
        if super().has_option(section, key):
            
            
            return expand_env_var(super().get(section, key, **kwargs))
        if deprecated_section:
            if super().has_option(deprecated_section, deprecated_key):
                self._warn_deprecate(section, key, deprecated_section, deprecated_key)
                return expand_env_var(super().get(deprecated_section, deprecated_key, **kwargs))
        return None
    def _get_environment_variables(self, deprecated_key, deprecated_section, key, section):