Yaml referencing other Yaml files

  * entityResolver.populateSpec is called for both catalog and yaml referencing items now to migrate attributes from the referee to the referred specs.
  * Reference catalog/YAML at any level
What is the reason for the discrepancy between this scenario and the one tested in `CatalogYamlTest. testParentCatalogDoesNotLeakBundlesToChildCatalogItems`?