Support datasets with >10k Parquet files
Fix this  ([internal](https://huggingface.slack.com/archives/C02V51Q3800/p1708702334005179?thread_ts=1708606229.359269&cid=C02V51Q3800))
![image](https://github.com/huggingface/datasets-server/assets/42851186/d8e546c1-7b5f-4e00-ac0a-05e955568e83)

I'll use a directory scheme like `config/train-part0/0000.parquet` up to `config/train-part9/9999.parquet`
Support datasets with >10k Parquet files: Fix this  ([internal](https://huggingface.slack.com/archives/C02V51Q3800/p1708702334005179?thread_ts=1708606229.359269&cid=C02V51Q3800))
![image](https://github.com/huggingface/datasets-server/assets/42851186/d8e546c1-7b5f-4e00-ac0a-05e955568e83)

I'll use a directory scheme like `config/train-part0/0000.parquet` up to `config/train-part9/9999.parquet`