Use lodkit.ClosedOntologyNamespace for ontology-based namespace objects

[lodkit.ClosedOntologyNamespace](https://github.com/lu-pl/lodkit?tab=readme-ov-file#namespace-tools) kills bugs. I do not want to upgrade `r11data` to the new LODKit 0.6 as there are many breaking changes, but the `ClosedOntologyNamespace` should definitely be used in `r11data`.