Implement backend API endpoint for query 5

[GoonerBrian]

Implement backend work for the following query from Deliverable 2:

Were countries with smaller harvested yield areas able to produce more crops?

This query will use the Country, Product, and Element entities, and will be connected through the Produces and Collection-method relations to

• identify which 3 countries have the lowest average yield area for a specific crop,
• identify which 3 countries have the highest average yield area for the same crop,
• the average production of that crop for each country,
• and calculate the ratio of yield area vs production for each country

This will allow the user to identify what, if any, trends exist between a country’s yield area and the amount of the crop they were able to produce.