Export plugin should be able to handle aggregation pipelines:

• All the logic should be encapsulated in the import-export plugin
• Open should happen with the same global event that is currently used to open queries: "open-export"
• Opening an export modal with pipeline should show the pipeline preview similar to the current first step of the modal form queries
  • We probably can skip showing the count altogether for the pipelines, but it would make sense to clarify this with product
  • For queries this preview allow to select "export full collection" option, as this doesn't make sense for aggregations, just a preview of the pipeline should be displayed instead
• There should be no option to select export fields (no second step as for queries, all fields should be exported and the form should proceed to file select after showing pipeline preview)
  • To determine export fields for the csv export we will use first document returned from the aggregation (we might change this particular logic later down the road, but this will be our starting point)