Add a processing time feature, formatter + tokens

Problem/Motivation

Total delivery time to the end-user consists of:
- Processing duration (production) in days (min / max)
- shipping duration (shipping company) in days (min / max)
= total delivery duration in days (min / max)

We should add functionality to also enter processing time (min / max) in a global setting.
For now, I don't think we need processing time per product, but maybe one day it could also be added (overriding the default)

Furthermore, the formatter should allow outputting information about the shipping time and provide different calculated variables:

• processing duration (min / max)
• shipping duration (min / max)
• total delivery duration (min / max) [=Sum]

So we're flexible in the template output and don't need calculations in twig.

I guess a translated string in the template will be good enough for output.
Additionally we should provide tokens for the global values. We can also add a minor follow-up to add tokens per product variation later for the eventually overridden values.

Steps to reproduce

Proposed resolution

Remaining tasks

User interface changes

API changes

Data model changes