Remove $facet in top level group stages#449

WaVEV wants to merge 1 commit intomongodb:mainmongodb/django-mongodb-backend:mainfrom

WaVEV:INTPYTHON-833-Refactor-Remove-$facet-usage-in-aggregation-pipelineWaVEV/django-mongodb-backend:INTPYTHON-833-Refactor-Remove-$facet-usage-in-aggregation-pipelineCopy head branch name to clipboard