feat: a utility for creating "permutation views" (#2552)

I'm working on a lancedb version of pytorch data loading (and hopefully
addressing https://github.com/lancedb/lance/issues/3727).

However, rather than rely on pytorch for everything I'm moving some of
the things that pytorch does into rust. This gives us more control over
data loading (e.g. using shards or a hash-based split) and it allows
permutations to be persistent. In particular I hope to be able to:

* Create a persistent permutation
* This permutation can handle splits, filtering, shuffling, and sharding
* Create a rust data loader that can read a permutation (one or more
splits), or a subset of a permutation (for DDP)
* Create a python data loader that delegates to the rust data loader

Eventually create integrations for other data loading libraries,
including rust & node

nodejs/src/table.rs

@@ -26,7 +26,7 @@ pub struct Table {
 }
 
 impl Table {
-    fn inner_ref(&self) -> napi::Result<&LanceDbTable> {
+    pub(crate) fn inner_ref(&self) -> napi::Result<&LanceDbTable> {
         self.inner
             .as_ref()
             .ok_or_else(|| napi::Error::from_reason(format!("Table {} is closed", self.name)))