

**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
#
#
import functools
import json
import logging
import multiprocessing
import os
import pathlib
import re
import shlex
import subprocess
import sys
import warnings
from base64 import b64encode
from collections import OrderedDict
from configparser import _UNSET, ConfigParser, NoOptionError, NoSectionError  
from json.decoder import JSONDecodeError
from typing import Dict, List, Optional, Union
from airflow.exceptions import AirflowConfigException
from airflow.secrets import DEFAULT_SECRETS_SEARCH_PATH, BaseSecretsBackend
from airflow.utils.module_loading import import_string
log = logging.getLogger(__name__)
if not sys.warnoptions:
    warnings.filterwarnings(action='default', category=DeprecationWarning, module='airflow')
    warnings.filterwarnings(action='default', category=PendingDeprecationWarning, module='airflow')
def expand_env_var(env_var):