Provide samples for using Python Connector with Django

[Django](https://www.djangoproject.com/) is one of the most widely used Python web frameworks. We should look at providing samples on how to connect to a Cloud SQL database using the Python Connector and Django.

What makes this a more difficult feat is that the default [Django backend](https://docs.djangoproject.com/en/4.1/ref/databases/) for Postgres is [`psycopg2`](https://github.com/psycopg/psycopg2) and for MySQL is [`mysqlclient`](https://github.com/PyMySQL/mysqlclient) or [`mysql-connector-python`](https://github.com/mysql/mysql-connector-python), which are not currently supported with the Python Connector.

- [Django Postgres](https://docs.djangoproject.com/en/4.1/ref/databases/#postgresql-notes)
- [Django MySQL](https://docs.djangoproject.com/en/4.1/ref/databases/#mysql-db-api-drivers)