**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">


tests/www/views/test_views.py
#
#
#
import os
from unittest import mock
import pytest
from airflow.configuration import initialize_config
from airflow.plugins_manager import AirflowPlugin, EntryPointSource
from airflow.www.views import get_safe_url, truncate_task_duration
from tests.test_utils.config import conf_vars
from tests.test_utils.mock_plugins import mock_plugin_manager
from tests.test_utils.www import check_content_in_response, check_content_not_in_response
def test_configuration_do_not_expose_config(admin_client):
    with conf_vars({('webserver', 'expose_config'): 'False'}):
        resp = admin_client.get('configuration', follow_redirects=True)
    check_content_in_response(
        [
            'Airflow Configuration',
            '# Your Airflow administrator chose not to expose the configuration, '
            'most likely for security reasons.',
        ],
        resp,
    )
@mock.patch.dict(os.environ, {"AIRFLOW__CORE__UNIT_TEST_MODE": "False"})
def test_configuration_expose_config(admin_client):