Optimize ZIP format inference
**Is your feature request related to a problem? Please describe.**
When hundreds of ZIP files are present in a dataset, format inference takes too long.

See: https://github.com/bigscience-workshop/data_tooling/issues/232#issuecomment-986685497

**Describe the solution you'd like**
Iterate over a maximum number of files.

CC: @lhoestq 
