metadata extraction resource

An example set of files used for testing metadata extraction to json-ld. The isPartOf in associatedMedia has not been added yet, one has manually been inserted in .hs/dataset_metadata.json

本示例文件集用于测试面向JSON-LD（JavaScript Object Notation for Linked Data）的元数据提取工作。关联媒体（associatedMedia）字段内的isPartOf属性尚未完成添加，目前已在.hs/dataset_metadata.json文件中手动插入了一条该属性的示例条目。