Add a skip layer guidance node that can also skip single layers.

This one should work for skipping the single layers of models like Flux
and Auraflow.

If you want to see how these models work and how many double/single layers
they have see the "ModelMerge*" nodes for the specific model.

nodes.py

@@ -2133,6 +2133,7 @@ def init_builtin_extra_nodes():
         "nodes_lora_extract.py",
         "nodes_torch_compile.py",
         "nodes_mochi.py",
+        "nodes_slg.py",
     ]
 
     import_failed = []