Delete legacy JSON metadata

add dataset_info in dataset metadata

remove dummmy data

fix task_ids

Align more metadata with other repo types (models,spaces) (#4607)

Fix typo in train split name (#3751)

Update files from the datasets library (from 1.18.0)

Update files from the datasets library (from 1.7.0)

Update files from the datasets library (from 1.6.0)

Update files from the datasets library (from 1.3.0)

Update files from the datasets library (from 1.2.0)