/first-rows to first-rows-from-streaming
Part of https://github.com/huggingface/datasets-server/issues/755

>  Implement first-rows-from-streaming job runner at config level (It already exist as /first-rows)

`/first-rows processing` step will be renamed to `first-rows-from-streaming` and new source of split validation will be `/split-names-from-streaming` result instead of using library.

/first-rows to first-rows-from-streaming: Part of https://github.com/huggingface/datasets-server/issues/755

>  Implement first-rows-from-streaming job runner at config level (It already exist as /first-rows)

`/first-rows processing` step will be renamed to `first-rows-from-streaming` and new source of split validation will be `/split-names-from-streaming` result instead of using library.
