Compositor: New Posterize Node

The posterize node limits the number of colors per channel.
This is useful to generate masks or to generate stylized images

Both the tiled and full-frame implementation are included in this patch

{F10314012}

Reviewed By: manzanilla, jbakker

Differential Revision: https://developer.blender.org/D12304

release/scripts/startup/nodeitems_builtins.py

@@ -333,6 +333,7 @@ compositor_node_categories = [
         NodeItem("CompositorNodeGamma"),
         NodeItem("CompositorNodeExposure"),
         NodeItem("CompositorNodeColorCorrection"),
+        NodeItem("CompositorNodePosterize"),
         NodeItem("CompositorNodeTonemap"),
         NodeItem("CompositorNodeZcombine"),
     ]),