Fix top-level endpoint grouping by defaulting tags to endpoint url path
Fix top-level endpoint grouping by defaulting tags to endpoint url path

- Modify get_operations
  - add logic to default to tags based on their endpoint url_path
  - ex: /api/v2/assets —> tag will be assets
  - ex: /api/v2/assets/trailers —> tag will be assets
aioTV/django-rest-swagger,aioTV/django-rest-swagger,aioTV/django-rest-swagger