Remove the support for importing content details from the ObjectStore

[marekhorst]

#1361 pull request (closing the #1298 issue) introduced the new aggregation subsystem based content importer module while still supporting an old, ObjectStore based, approach which is meant to be considered as obsolete once the new aggregation subsystem is integrated with production environment.

We should remove the support for the obsolete ObjectStore based importer by disabling this functionality in the content_url_chain subworkflow and removing all unneeded classes and resources.

Here is the initial list of things to be removed (preserving my incomplete notes created while developing #1298):

• parameters to be removed from the primary_main workflow definition: import_content_object_store_location, import_content_objectstores_csv
• parameters to be removed from various workflow definitions: objectstore_service_location, approved_objectstores_csv, blacklisted_objectstores_csv, objectstore_facade_factory_classname
• workflow definitions: importer/content_url/core including the ones covering integration tests
• classes: ObjectStoreIdentifierDatastoreBuilder, ObjectStoreDocumentContentUrlImporterMapper, ObjectStoreDocumentContentUrlImporterMapperTest, ObjectStoreFacade, WebServiceObjectStoreFacade, ExceptionThrowingObjectStoreFacadeFactory, MockObjectStoreFacadeFactory and possibly other referenced classes which are not used elsewhere
• JSON resources bound to tests
• sample_data.txt and sample_data.gz should be checked and potentially removed