feat(datafusion): implement the project node to add the partition columns defined in Iceberg.

Implement physical execution plan node that projects Iceberg partition columns
from source data, supporting nested fields and all Iceberg transforms.

Author: fvaleye

crates/integrations/datafusion/src/physical_plan/mod.rs

@@ -18,6 +18,7 @@
 pub(crate) mod commit;
 pub(crate) mod expr_to_predicate;
 pub(crate) mod metadata_scan;
+pub(crate) mod project;
 pub(crate) mod scan;
 pub(crate) mod write;