Added support to load model config from Metadata. (#399)

* Implement GGUF metadata extraction function

Added function to extract metadata from GGUF files.

* Updated the GGUF model loading and patching classes to include metadata handling.

* Clean up return logic for extra metadata

This should be more future proof in case we need to return other attributes in the future. Possible breaking change for anyone using `gguf_sd_loader` directly either way, though.

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Co-authored-by: City <125218114+city96@users.noreply.github.com>

nodes.py

@@ -165,9 +165,9 @@ class UnetLoaderGGUF:
 
         # init model
         unet_path = folder_paths.get_full_path("unet", unet_name)
-        sd = gguf_sd_loader(unet_path)
+        sd, extra = gguf_sd_loader(unet_path)
         model = comfy.sd.load_diffusion_model_state_dict(
-            sd, model_options={"custom_operations": ops}
+            sd, model_options={"custom_operations": ops}, metadata=extra.get("metadata", {})
         )
         if model is None:
             logging.error("ERROR UNSUPPORTED UNET {}".format(unet_path))
@@ -319,3 +319,4 @@ NODE_CLASS_MAPPINGS = {
     "QuadrupleCLIPLoaderGGUF": QuadrupleCLIPLoaderGGUF,
     "UnetLoaderGGUFAdvanced": UnetLoaderGGUFAdvanced,
 }
+