Refactor IngredientController.modules to be a dict

[cydanil]

IngredientController.modules is a list that contains the different UIs ({Description,Ingredient,Instructions,Notes}EditorModules) in the attached to a recipe.

These are now kept in a list, IngredientController.modules, where they are accessed by index.
The correct index for a given module can be found in IngredientController.module_tab_by_name.

This tends to litter the code with a bunch of hardcoded indices, even though the correct way to get a controller is:

idx = i_controller.module_tab_by_name["ingredients"]
ingredients = i_controller.module[idx]

Historically, each EditorModule was kept straight in the class as class attributes. I'm not sure what motivated this change.

However, it would be nicer to simply refactor IngredientController.modules to be a dictionary, to access the modules by their names instead of indices:

ingredients = i_controller.module["ingredients"]

[maweki]

Do we know the attributes beforehand? Then attribute accessors would be a better solution. We get better types from that.

[cydanil]

We do, it used to be so before, I don't know what motivated the change.

[maweki]

I mean, the we would emulate data classes instead of dicts.