Plan for Book 3.0 release

Problem/Motivation

The 3.0 release of the Book module → will have some big changes, including:

• The removal of the book content type. See book/issues/2871733 🌱 Remove the book content type from the book module Active
• Allowing per book child content type configuration. See book/issues/3173808 ✨ Make book child content-type configurable per enabled book content-type Postponed

These changes may or may not have an impact on the 3.x version of the booktree module.

Remaining tasks

Determine if the Book 3.0 changes will impact the 3.x booktree module.