Django-datadog-logger

- Fixed case where accessing request.auth may raise errors

- Removed dependency on Celery package, fixed import error

- Removed dependency on Celery package

- Datadog formatter: avoid recursion loop when accessing WSGI request
auth attribute

- Improved support for request version reporting in <span
class="title-ref">http.request_version</span>
- Add support for <span
class="title-ref">http.url_details.view_name</span>

- Added support for HTTP Accept header as <span
class="title-ref">http.accept</span>