Feature: Specify required equipment in recipes and config

[langston-barrett]

Some recipes require or are easier with a piece of specialized equipment, such as a food processor, blender, or hand mixer. We should allow recipes to say what they require, and allow users to specify in the configuration what equipment they have.

When viewing a recipe, we should leave out equipment by default, but warn if the recipe requires something the user doesn't have.

Like units, we should probably have a list/enumeration of recognized equipment (common stuff like a blender) but allow for unknown equipment to be specified.