Improve swagger documentation for method-based DRF endpoints

[jonboiser]

The ask: more detailed documentation on swagger, like what is done for the more full-featured ModelViewSets

For example, this cleartasks endpoint is implemented as a method on the main viewset....

kolibri/kolibri/core/tasks/api.py

Lines 248 to 259 in 9b29c12

	@action(methods=["post"], detail=False)
	def cleartask(self, request):
	# Given a single task ID, clear it from the queue
	task_id = request.data.get("task_id")
	if not task_id:
	return Response({})
	for _queue in self.queues:
	_queue.clear_job(task_id)
	return Response({"task_id": task_id})

...The swagger docs will show a comment, but no extra documentation about the parameters

Compare to this endpoint, which seems to automatically create documentation on the payload shape

[rtibbles]

Guessing the information is introspected from the serializer - so this will be the case for any endpoint we setup that does not have an explicit serializer associated with it. Will look into alternatives here.

[jonboiser]

I'm having a hard time finding a newbie-level tutorial on this, but I think if you can somehow provide an OpenAPI schema for these endpoints (maybe in some external YML file?), Swagger will be able to show it on its API explorer.

It might also be beneficial just do the work and making really basic Serializer classes for these endpoints, instead of sending these Response(dictionaryLiteral) type responses.

[rtibbles]

This was addressed by automatic serializer generation here: #8138 to help with this.