Feature Request -> Option to set root node for selection

[egandalf]

I have a customer who wants to be able to set rules for which categories may be used by content type. They need to categorize landing pages, news pages, and uploaded documents differently and want the restriction to be enforced through configuration.

Adding a category to a document should only come from the "Documents" root node, for example. This can't be directly managed with permissions as someone might be uploading documents as part of adding a news article. Validation rules can be applied, but this is an after-selection activity. What they need is to not show invalid options to begin with.

Preference would be to limit categories via property configuration.