

**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/models/baseoperator.py
"""Required by TaskMixin"""
        return [self]
    def _set_relatives(
        self,
        task_or_task_list: Union[TaskMixin, Sequence[TaskMixin]],
        upstream: bool = False,
    ) -> None:
        """Sets relatives for the task or task list."""
        if not isinstance(task_or_task_list, Sequence):
            task_or_task_list = [task_or_task_list]
        task_list: List["BaseOperator"] = []
        for task_object in task_or_task_list:
            task_object.update_relative(self, not upstream)
            relatives = task_object.leaves if upstream else task_object.roots
            task_list.extend(relatives)
        for task in task_list:
            if not isinstance(task, BaseOperator):
                raise AirflowException(
                    "Relationships can only be set between "
                    "Operators; received {}".format(task.__class__.__name__)
                )
        
        
        dags = {
            task._dag.dag_id: task._dag  
            for task in self.roots + task_list
            if task.has_dag()  
        }