www/py-dj41-drf-spectacular: New port

Note: Copied from www/py-drf-spectacular, required for NetBox 3.5.

This project has 3 goals:

* Extract as much schema information from DRF as possible.
* Provide flexibility to make the schema usable in the real world (not
  only toy examples).
* Generate a schema that works well with the most popular
  client generators.

The code is a heavily modified fork of the DRF OpenAPI generator, which
is/was lacking all of the below listed features:

* Serializers modelled as components. (arbitrary nesting +
  recursion supported)
* @extend_schema decorator for customization of APIView, Viewsets,
  function-based views, and @action
* Authentication support (DRF natives included, easily extendable)
* Custom serializer class support (easily extendable)
* SerializerMethodField() type via type hinting or @extend_schema_field
* i18n support, Tags extraction, Description extraction from docstrings
* Request/response/parameter examples, Callback operations
* Vendor specification extensions (x-*) in info, operations, parameters,
  components, and security schemes
* Sane fallbacks and sane operation_id naming (based on path)
* Schema serving with SpectacularAPIView (Redoc and Swagger-UI views are
  also available)
* Optional input/output serializer component split