Allow to move content type out of inheritance from UI

[bjarnef]

Content types can use compositions or nested content types to inherit properties.
I guess there are pros and cons for both approaches.

However when migrating projects there are often nested content types.

We can changes parent id in database, but often I think it would we nice to handle this from UI is backoffice, which could change parent id and possible copy inherited properties.

In a migrated project I noticed the inheritance also may cause issues with ModelsBuilder models generation and if content type already is used as a content node. #15604