Remove binarization step

Will not work with the new way of storing images.

src/htrflow_core/pipeline/steps.py

@@ -5,7 +5,7 @@
 from htrflow_core.models.importer import all_models
 from htrflow_core.postprocess.reading_order import left_right_top_down, order_region_with_marginalia
 from htrflow_core.serialization import get_serializer
-from htrflow_core.utils.imgproc import binarize, write
+from htrflow_core.utils.imgproc import write
 from htrflow_core.utils.layout import estimate_printspace
 from htrflow_core.volume.volume import Volume
 
@@ -65,13 +65,6 @@ class TextRecognition(Inference):
     pass
 
 
-class Binarization(PipelineStep):
-    def run(self, volume):
-        for page in volume:
-            page.image = binarize(page.image)
-        return volume
-
-
 class WordSegmentation(PipelineStep):
     requires = [TextRecognition]