Add DRF Support

[sjbitcode]

Currently the cbv check consists of an attribute check on the view function:

django-cbv-inspect/cbv_inspect/utils.py

Lines 86 to 90 in fad3cc9

	def is_cbv_view(func: Callable) -> bool:
	"""
	Determine if a function is a result of a CBV as_view() call.
	"""
	return hasattr(func, "view_class")

This isn't compatible with DRF's views (via browsable API) because of the extra processing in DRF's APIView and ViewSetMixin; it is possible by checking the cls attribute but we need to make sure there aren't any side effects with other DRF things like the wrapped request/response objects.