Django-composed-configuration

* Add Sentry support if the `sentry-sdk` package is installed and the `SENTRY_DSN` environment variable is set in production
* Simplify the logging configuration, also allowing it to be mutated
* Filter static file requests from logged output

* Use pathlib for BASE_DIR
* Users can define: `BASE_DIR = Path(__file__).resolve(strict=True).parent.parent`
* Configure robust HTTPS serving in production
* Move files out of the `configuration` sub-directory
* Now, import as: `from composed_configuration import DevelopmentBaseConfiguration`
* Remove `SelectRelatedManager`

Initial `django-composed-configuration` release