Translate "Merge Container RocksDB in DN" doc into Mandarin Chinese

This is the "Merge Container RocksDB in DN" doc in the nightly build: https://ozone.apache.org/docs/edge/feature/dn-merge-rocksdb.html

This is a wish list to translate the doc into Mandarin, because we don't have it today: https://ozone.apache.org/docs/edge/zh/

Source of the original doc: https://github.com/apache/ozone/blob/master/hadoop-hdds/docs/content/feature/dn-merge-rocksdb.md
Translation should be added as: hadoop-hdds/docs/content/feature/dn-merge-rocksdb.zh.md