More hub centric docs
Let's have more hub-centric documentation in the datasets docs

Tutorials
- Add “Configure the dataset viewer” page
- Change order:
  - Overview
    - and more focused on the Hub rather than the library
  - Then all the hub related things
    - and mention how to read/write with other tools like pandas
  - Then all the datasets lib related things in a subsection

Also:
- Rename “know your dataset” page to “Explore your dataset”
- Remove “Evaluate Predictions” page since it's 'evaluate' stuff (or move to legacy section ?)

TODO:
- [ ] write the “Configure the dataset viewer” page