Feature: Add sections metadata to segment aggregates of content modules

[jurra]

Use case description

A section folder containing a section metadata, perhaps level 1. Based on this metadata description and the child directories containing also content.yaml metadata, generate automatically these sections.

Exceptions

• An empty section
• An empty module

Implementation ideas

• Avoid nesting the different metadata aggregates, instead create different types that are referenced
• Allow different methods and ways of extracting the metadata aggregates including directory hierarchy but also perhaps file naming conventions.
• Consider automatically populating fields also in the contents.yaml not all data needs to be populated manually.