Create Drupal 11 documentation pages for Field Group

Problem/Motivation

I couldn't find a Drupal 11 documentation page for the great Field Group module, which is a shame.

Steps to reproduce

Proposed resolution

I created a Guide:
https://www.drupal.org/docs/extending-drupal/contributed-modules/field-g... →

... and a short intro Page:
https://www.drupal.org/docs/extending-drupal/contributed-modules/field-g... →

Remaining tasks

• Add Documentation → link on the project page ( https://www.drupal.org/project/field_group → ) under "Resources"
• Rename http://drupal.org/node/1017838 to Documentation (D7) (or delete?)
• Get the Field Group → Guide reviewed by Contributed modules maintainers and added to the menu.
• Transfer relevant information from the old Drupal 7 documentation to new Pages under Field Group →

User interface changes

API changes

Data model changes