Aggregate approximate recipe prices

[jayaddison]

Per-recipe price approximation should be possible once we have ingredient prices available that we can aggregate.

These approximate prices should be included in the search engine index so that we can allow users to search based on price ranges.

In addition it may be useful to calculate and include a 'relative price score' for each recipe in the search index -- it should be a score that is relative to the 'average' price of similar recipes. For example, a dessert recipe that calls for a few expensive fruit ingredients might have a price score of 2.5x relative to other desserts. Similarly a ramen noodle recipe might have a 0.5x score relative to other small meals.

Approximate prices for each recipe may be exposed via the search API via an abstract rating, perhaps similar to a star rating (1-5). Using the user's localized currency symbol could be an option here.