Add document preprocessing submodules to OCR configuration

- Introduced new `SubPipelines` section in `ocr_config.yaml` to include `DocPreprocessor` settings.
- Added submodules for document orientation classification and unwarping, enhancing the OCR pipeline's ability to process various document formats and improve accuracy.

paddlex/ocr_config.yaml

@@ -14,3 +14,18 @@ SubModules:
     model_dir: null
     batch_size: 1
     score_thresh: 0
+
+SubPipelines:
+  DocPreprocessor:
+    pipeline_name: doc_preprocessor
+    use_doc_orientation_classify: true
+    use_doc_unwarping: true
+    SubModules:
+      DocOrientationClassify:
+        module_name: doc_text_orientation
+        model_name: PP-LCNet_x1_0_doc_ori
+        model_dir: null
+      DocUnwarping:
+        module_name: image_unwarping
+        model_name: UVDoc
+        model_dir: null