www/py-drf-spectacular: New port

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