[Advanced lists] add guide to CKE5 documentation

[godai78]

Add the advanced list information and demo.

Based on talk in the core team, this should be added to the existing lists guide to ultimately replace the old feature once it's extinguished.

[godai78]

Base user-oriented info and sample: https://ckeditor.com/blog/ckeditor-5-v34.0.0-with-redesigned-lists-new-styles-implementation-and-extended-dll-builds/#new-redesigned-lists

[apadol-cksource]

The feature is used by import from Word so should be also available in the documentation

Known issues:

• No support for track changes
• No support for todo lists
• Not used in any of the builds. All builds use the old lists for now

[godai78]

Merged: Merged: https://github.com/ckeditor/ckeditor5/pull/12489