Portion "units"

[ModProg]

Is your feature request related to a problem? Please describe.
When backing recipes often can be adjusted to the baking sheet you use, i.e. do you use a Springform 23cm vs 28cm. While it is obviously possible to calculate these by hand everytime you bake and enter the correct ratio in the portions field it isn't really convinient.

Describe the solution you'd like
Define a list of “backing units” with the correct ratio assigned.
When creating a backing recipe you can set the portions to "1 28cm Springform" and then be able to select e.g. a 23cm Springform when I want to bake a smaller version.

Describe alternatives you've considered
A less convinient solution could also be to allow defining custom “steps” for each recipe's portion size selector, i.e. add a list of common “portion sizes” to a recipe, like "0.3" or "0.6".