Feature: Express dependencies between steps of the recipe

[langston-barrett]

I often cook with others. It's hard to decide on the fly who should take on which steps of a recipe, especially since some steps have dependencies on others (e.g. you have to chop the garlic before you can put it in the pan). It would be nice to have a clear picture (maybe even a vizualization??) of what the dependencies are and how to minimize the cooking time.