LinkedDataHub packages

[namedgraph]

Introduce first-class package support in LinkedDataHub

This PR adds first-class support for packages in LinkedDataHub, including server-side implementation, admin tooling, and HTTP-level test coverage for install/uninstall workflows.

Summary of changes

• Package install / uninstall

  • Implements package installation and removal at the dataset level.
  • Uses Graph Store Protocol PATCH to add and remove owl:imports, allowing package ontologies, stylesheets, and related assets to be cleanly composed and detached.

• Admin tooling

  • Adds and refactors admin scripts for package installation.
  • Fixes ontology import handling during install/uninstall.

• HTTP test coverage

  • Introduces a dedicated set of HTTP tests covering:

    • Successful package install and uninstall
    • Install → uninstall sequences
    • Failure and edge cases

• Refactoring and cleanup

  • Replaces LinkedDataClient usage with GraphStoreClient.
  • Refactors XSLTMasterUpdater.
  • Improves resource handling and response lifecycle management.

• Ontology and security adjustments

  • Updates the SKOS package ontology (imports and URI fixes).
  • Removes unused VIVO ontology.
  • Restricts public access by removing /transform from allowed endpoints.

• Build / infra

  • Updates dependencies and snapshot versions.
  • Fixes Varnish BAN handling in ontology cache clearing.

Impact

This change establishes a modular, composable packaging mechanism for LinkedDataHub, enabling reusable ontologies, layouts, and functionality to be installed and removed declaratively, with proper HTTP semantics and test coverage.

Testing

• New HTTP tests under http-tests/admin/packages/ cover install and uninstall scenarios.