Create way to store consumption allocation data

[rbroth]

For each survey, we want to store a "spreadsheet" that shows how the scientists processed the consumption data into food_genus-compatible format. For example, IHS4 says "this household consumed 100g of rice" - this is too broad for our purposes; we make the assumption that the rice consumed was 50-50 brown rice and white rice, and record the allocation factor i.e. "In the input dataset from IHS4, we replaced every instance of 'rice - 100g' with 'brown rice - 50, white rice - 50g'

[rbroth]

This data will be viewed by end-user when they want to know how we processed food consumption survey data before loading it into the system. Scientific users may disagree with out assumptions and want to do their own pre-processing of consumption data before loading it into our system via bring their own data (e.g. Replace every instance of "rice - 100g" with "brown rice -70g, white rice - 30g"