add general purpose function calling handler

Author: okaris

llama_cpp/llama_chat_format.py

@@ -4157,8 +4157,7 @@ def gguf_function_calling(
 
     function_calling_template = None
     if hasattr(llama, 'model_path'):
-        from llama_cpp.llama import Llama
-        metadata = Llama.metadata
+        metadata = llama.metadata
         if metadata and "tokenizer.chat_template" in metadata:
             function_calling_template = metadata["tokenizer.chat_template"]