This function should do the following:

Given an instance of the society-wide structure we currently use, aggregate the values from the structures to create one aggregated instance of the same schema; this may be challenging, as for some values, we'll need the aggregate; for some, we'll need mean; and for others, perhaps something else?

I will want to confirm with Pavel or Nikhil how they calculate multi-year impacts just to be 100.0% certain this function is doing the math properly.

• Create function to aggregate a series of SocietyWideImpact items into one aggregated total output
• Write tests for the above function
• Modify function to remove unneeded outputs - only want to aggregate top-line items - we only want the data needed for the overview page
• Create schema representing aggregated impacts
• Re-open PR off of a clone instead of a fork