Support multiple machines per recipe

[lewark]

To reduce duplication, the system could allow recipes to specify multiple supported machines, like allowing food recipes to use either a smoker or a furnace.

This could be handled by making the "machine" field in recipes an array, or by adding a "provides" field to machines that allows them to act as multiple. I'm currently leaning toward using the device-provides method, since it keeps recipe definitions from needing to repeat several machine names. The system already supports virtual slot mapping, which removes any concerns of inventory slots not lining up.

Since smokers are faster than furnaces, it should be possible to prioritize them over plain furnaces as well. A benefit of handling it on the recipe side would be that priority could be set based on the array order. Alternatively, a "priority" field could be added to machines like is already present for storage.

To resolve the same duplication problem for electric furnaces, fuel could be handled as part of the device specification instead of the recipe.