#4208: New permission for administering metastore settings

[stefan-korn]

fixes #4208

• [ ] Test coverage exists
• [ ] Documentation exists

QA Steps

• [ ] check permissions under admin/people/permissions at section Metastore and see the new permission 'Metastore: Administer Metastore Settings"
• [ ] grant this permission to a role
• [ ] check that the role with this permission can access admin/dkan/properties
• [ ] check that a role without this permission cannot access admin/dkan/properties