add cross-lingual dst data

data/crosswoz_en/README.md

data/crosswoz_en/human_val_data.zip

data/crosswoz_en/mt_data.zip

data/crosswoz_en/ontology_translate.py

data/crosswoz_en/vocab_dict.json

data/multiwoz_zh/README.md

data/multiwoz_zh/human_val_data.zip

data/multiwoz_zh/mt_data.zip

data/multiwoz_zh/ontology_translate.py

data/multiwoz_zh/vocab_dict.json