Allow to disable specialized tokenizations (again)

In PR #2773, I added the `chinese`, `hebrew`, `japanese` and `thai`
feature flags to allow melisearch to be built without huge specialed
tokenizations that took up 90% of the melisearch binary size.
Unfortunately, due to some recent changes, this doesn't work anymore.
The problem lies in excessive use of the `default` feature flag, which
infects the dependency graph.

Instead of adding `default-features = false` here and there, it's easier
and more future-proof to not declare `default` in `milli` and
`meilisearch-types`. I've renamed it to `all-tokenizers`, which also
makes it a bit clearer what it's about.

milli/src/update/index_documents/mod.rs

@@ -1581,7 +1581,7 @@ mod tests {
         assert_eq!(count, 4);
     }
 
-    #[cfg(feature = "default")]
+    #[cfg(feature = "chinese")]
     #[test]
     fn test_meilisearch_1714() {
         let index = TempIndex::new();