Store regional ingredient prices

[jayaddison]

• Persistence: static data rendered-to-file with timestamps; cache-friendly
• Format: GeoJSON; client-query-friendly
• Identifiers: product ID (as present in RecipeML hrefs sent to client)
• Anonymization: Bounding box sizes, aggregation, reduced precision

[jayaddison]

It would be nice to implement https://github.com/openculinary/infrastructure/issues/8 before this change is introduced.