Change split names upstream and source
Partial fix for https://github.com/huggingface/datasets-server/issues/755

- Changing the predecessor of split-names to dataset-info
- Changing source of split-names (db instead of dataset lib in streaming mode)
Change split names upstream and source: Partial fix for https://github.com/huggingface/datasets-server/issues/755

- Changing the predecessor of split-names to dataset-info
- Changing source of split-names (db instead of dataset lib in streaming mode)