Add Hub dashboard in admin app
A simple dashboard in gradio to show the number of datasets per type (parquet, json, dataset script etc) and the viewer coverage of trending datasets (can be extended later if needed).

The idea is to follow if users are still using dataset scripts often or if usage is going to our goal: less and less datasets defined with code.

The second idea is to see if the trending datasets are well supported by the datasets-server, which is one of our main priorities.

I used two endpoints for this:
- `/is-valid`
- `/admin/num-dataset-infos-by-builder-name` that I created

Fix https://github.com/huggingface/datasets-server/issues/1857
Add Hub dashboard in admin app: A simple dashboard in gradio to show the number of datasets per type (parquet, json, dataset script etc) and the viewer coverage of trending datasets (can be extended later if needed).

The idea is to follow if users are still using dataset scripts often or if usage is going to our goal: less and less datasets defined with code.

The second idea is to see if the trending datasets are well supported by the datasets-server, which is one of our main priorities.

I used two endpoints for this:
- `/is-valid`
- `/admin/num-dataset-infos-by-builder-name` that I created

Fix https://github.com/huggingface/datasets-server/issues/1857