feat: make it possible to opt in to using the v2 format (#1352)

This also exposed the max_batch_length configuration option in
python/node (it was needed to verify if we are actually in v2 mode or
not)

nodejs/src/lib.rs

@@ -56,6 +56,7 @@ pub enum WriteMode {
 /// Write options when creating a Table.
 #[napi(object)]
 pub struct WriteOptions {
+    /// Write mode for writing to a table.
     pub mode: Option<WriteMode>,
 }