GitLab

* Adding `top_k` and `sort` arguments to `text-classification` pipeline.

- Deprecate `return_all_scores` as `top_k` is more uniform with other
  pipelines, and a superset of what `return_all_scores` can do.
  BC is maintained though.
  `return_all_scores=True` -> `top_k=None`
  `return_all_scores=False` -> `top_k=1`

- Using `top_k` will imply sorting the results, but using no argument
  will keep the results unsorted for backward compatibility.

* Remove `sort`.

* Fixing the test.

* Remove bad doc.