Map to Periodic Table of Foods Initiative (PTFI) metadata schema

It would be good to coordinate with folks from the [Periodic Table of Foods Initiative](https://foodperiodictable.org/) to ensure MIFC covers and maps to the content of the PTFI metadata schema. We've already done a preliminary pass at this (e.g., food_acquisition_latitude is currently mapped to PTFI:Collection_Type). It would be good, however, to update and keep in sync with the latest on ongoing versions of PTFI's metadata schema.

Start by comparing MIFC's current metadata mappings, including the food_acquisition_latitude example, with the latest PTFI metadata schema. Coordinate with PTFI contributors and update the mapping so MIFC covers the relevant schema content; done means the mappings reflect the current PTFI version and an approach for keeping them synchronized is documented.

Written by the indexing model from the issue text.