Add `useLiteralNames` option to disable column name normalization

Add `useLiteralNames` option to disable column name normalization

This behavior is useful to preserve data when an input CSV has multiple columns with the same normalized name. By default, `CSVNormalizer` will remove these duplicate columns (the data from the last column is used).

Note that columns with the same *literal* name are still removed even when `useLiteralNames` is `true`. If you need to preserve columns with the same literal name, use a lower-level transformation (e.g., `CSVTransformer`).