**Description**

`BigQueryInsertJobOperator` requires the submission of a `configuration` parameter in the form of a dict.  Unfortunately, if this contains a large SQL query - especially one that is formatted with new lines - then this cannot currently be rendered very nicely in the UI.

<img width="1670" alt="Screenshot 2021-07-15 at 15 39 33" src="https://user-images.githubusercontent.com/967119/125806943-839d57a9-d4a0-492d-b130-06432b095239.png">

**Use case / motivation**

The issue with this is that it's impossible to copy and paste the rendered query out of the Airflow UI, into a BigQuery browser and run it without lots of manual edits which is time wasted when troubleshooting problems.

**Are you willing to submit a PR?**

Yes.  My current thought process around this would be to add an optional SQL parameter to the operator which, if provided, would be added into the configuration and could therefore have its own template field and SQL renderer.

e.g.

<img width="1570" alt="Screenshot 2021-07-14 at 14 18 09" src="https://user-images.githubusercontent.com/967119/125808200-5f30b8f4-4def-48a7-8223-82afdc65c973.png">


airflow/providers/google/cloud/operators/bigquery.py
"""
    This operator deletes an existing dataset from your Project in Big query.
    https://cloud.google.com/bigquery/docs/reference/rest/v2/datasets/delete
    .. seealso::
        For more information on how to use this operator, take a look at the guide:
        :ref:`howto/operator:BigQueryDeleteDatasetOperator`
    :param project_id: The project id of the dataset.
    :type project_id: str
    :param dataset_id: The dataset to be deleted.
    :type dataset_id: str
    :param delete_contents: (Optional) Whether to force the deletion even if the dataset is not empty.
        Will delete all tables (if any) in the dataset if set to True.
        Will raise HttpError 400: "{dataset_id} is still in use" if set to False and dataset is not empty.
        The default value is False.
    :type delete_contents: bool
    :param gcp_conn_id: (Optional) The connection ID used to connect to Google Cloud.
    :type gcp_conn_id: str
    :param bigquery_conn_id: (Deprecated) The connection ID used to connect to Google Cloud.
        This parameter has been deprecated. You should pass the gcp_conn_id parameter instead.