Utility trait for stats-based skipping logic (#357)

Parquet footer stats allow data skipping, very similar to Delta file
stats. Except parquet isn't quite as convenient to work with and
arrow-parquet doesn't even try to help (it can't, because arrow-compute
expressions are opaque, so there's no way to traverse and rewrite them
into stats-based skipping predicates).

We implement row group skipping support by traversing the same push-down
predicate that delta-kernel already uses to extract a for Delta file
skipping predicate. But instead of rewriting the expression, we evaluate
it bottom-up (no-copy, O(n) work where n is the number of nodes in the
expression).

This PR does not attempt to actually incorporate the new skipping logic
into the default reader. That (plus testing the integration) should
be a follow-up PR.

Author: scovich

kernel/src/engine/mod.rs

@@ -11,6 +11,9 @@ pub mod arrow_expression;
 #[cfg(any(feature = "default-engine", feature = "sync-engine"))]
 pub mod arrow_data;
 
+#[cfg(any(feature = "default-engine", feature = "sync-engine"))]
+pub mod parquet_stats_skipping;
+
 #[cfg(any(feature = "default-engine", feature = "sync-engine"))]
 pub(crate) mod arrow_get_data;