Lazy scorers (#2726)

* Refactoring of the score tweaker into `SortKeyComputer`s to unlock two features.

- Allow lazy evaluation of score. As soon as we identified that a doc won't
reach the topK threshold, we can stop the evaluation.
- Allow for a different segment level score, segment level score and their conversion.

This PR breaks public API, but fixing code is straightforward.

* Bumping tantivy version

---------

Co-authored-by: Paul Masurel <paul.masurel@datadoghq.com>

examples/deleting_updating_documents.rs

@@ -28,7 +28,7 @@ fn extract_doc_given_isbn(
     // The second argument is here to tell we don't care about decoding positions,
     // or term frequencies.
     let term_query = TermQuery::new(isbn_term.clone(), IndexRecordOption::Basic);
-    let top_docs = searcher.search(&term_query, &TopDocs::with_limit(1))?;
+    let top_docs = searcher.search(&term_query, &TopDocs::with_limit(1).order_by_score())?;
 
     if let Some((_score, doc_address)) = top_docs.first() {
         let doc = searcher.doc(*doc_address)?;