🔧(backend) make AI feature reach configurable

We want to be able to define whether AI features are available to
anonymous users who gained editor access on a document, or if we
demand that they be authenticated or even if we demand that they
gained their editor access via a specific document access.

Being authenticated is now the default value. This will change the
default behavior on your existing instance (see UPGRADE.md)

CHANGELOG.md

@@ -16,6 +16,10 @@ and this project adheres to
 - ✨(frontend) cursor display on activity #609
 - ✨(frontend) Add export page break #623
 
+## Changed
+
+- 🔧(backend) make AI feature reach configurable
+
 ## Fixed
 
 🌐(CI) Fix email partially translated #616