

**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
:type include_env: bool
        :param include_cmds: Should the result of calling any *_cmd config be
            set (True, default), or should the _cmd options be left as the
            command to run (False)
        :type include_cmds: bool
        :param include_secret: Should the result of calling any *_secret config be
            set (True, default), or should the _secret options be left as the
            path to get the secret from (False)
        :type include_secret: bool
        :rtype: Dict[str, Dict[str, str]]
        :return: Dictionary, where the key is the name of the section and the content is
            the dictionary with the name of the parameter and its value.
        """
        config_sources: Dict[str, Dict[str, str]] = {}
        configs = [
            ('default', self.airflow_defaults),
            ('airflow.cfg', self),
        ]
        self._replace_config_with_display_sources(config_sources, configs, display_source, raw)
        
        if include_env:
            self._include_envs(config_sources, display_sensitive, display_source, raw)
        
        if include_cmds:
            self._include_commands(config_sources, display_sensitive, display_source, raw)
        
        if include_secret:
            self._include_secrets(config_sources, display_sensitive, display_source, raw)
        return config_sources
    def _include_secrets(self, config_sources, display_sensitive, display_source, raw):