

**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
val = self.get(section, key, **kwargs)
        try:
            return int(val)
        except ValueError:
            raise AirflowConfigException(
                f'Failed to convert value to int. Please check "{key}" key in "{section}" section. '
                f'Current value: "{val}".'
            )
    def getfloat(self, section, key, **kwargs):
        val = self.get(section, key, **kwargs)
        try:
            return float(val)
        except ValueError:
            raise AirflowConfigException(
                f'Failed to convert value to float. Please check "{key}" key in "{section}" section. '
                f'Current value: "{val}".'
            )
    def getimport(self, section, key, **kwargs):