Create documented workflow for updating FCT and Consumption data

[rbroth]

#279 we ran into an issue where the food_genus_id for pork changed in a Food Composition Table, but consumption data in the IHS4 was still using the old food_genus_id. How do we prevent this from happening in the future?

@LuciaSegovia @LouiseAnder @TomCodd @dzvoti @bgsandan

[rbroth]

@bgsandan plz give the issue a priority label

[LouiseAnder]

@dzvoti please could you help with the approach we take - as per metadata in approach, obviously requires different details. thanks!

[dzvoti]

@LouiseAnder we will do. I will share the metadata approach we developed with @LuciaSegovia and @rbroth see how we can adopt and modify it.