Two big features that are only barely related in the same guide. Seems
bad.

I did not check references to these guides yet, so some links may need
to be updated.

This reverts commit f5b9ed4f.

REASON: Translation work can not be done in the docrails repository

This is still an early draft, but let's add it to the index
to have it ready.

Use the list of guides available in documents.yaml to fill in the
menu in the index page instead of duplicating the list again. Also,
remove WIP guides from the menu.