Use the new field .status in the search UI

The field .status can have the values:

            Self::Active => "Aktiv",
            Self::Obsolete => "Obsolet",
            Self::Planned => "Geplant",
            Self::UnderDevelopment => "In Entwicklung",

The search UI uses these as follows:

• In the search result page: Warn users about datasets that are obsolete
• In the details page:
  • Warn users about datasets that are obsolete
  • Inform users if a dataset is not active

This MR needs to run against metadaten!876 (merged) running on localhost with adapted "api-proxy.js"