feat!: list_databases returns an iterator (#4442)

CatalogConnection.list_databases should return an iterator so that users
don't have to manually re-implement pagination. For those who do want
more control over pagination, add num_page_results and page_token to the
Iterator object, and also allow the iterator object to be created at a
specific page token.

nodejs/lancedb/index.ts

@@ -646,6 +646,6 @@ export async function connectNamespace(
 export {
   Catalog,
   CatalogOptions,
-  ListDatabasesResponse,
+  DatabaseNames,
   connectCatalog,
 } from "./catalog";