Separated llms from the main llm.py file and fixed some deprication bugs

examples/lightrag_api_openai_compatible_demo.py

@@ -2,7 +2,7 @@ from fastapi import FastAPI, HTTPException, File, UploadFile
 from pydantic import BaseModel
 import os
 from lightrag import LightRAG, QueryParam
-from lightrag.llm import openai_complete_if_cache, openai_embedding
+from lightrag.llm.openai import openai_complete_if_cache, openai_embed
 from lightrag.utils import EmbeddingFunc
 import numpy as np
 from typing import Optional
@@ -48,7 +48,7 @@ async def llm_model_func(
 
 
 async def embedding_func(texts: list[str]) -> np.ndarray:
-    return await openai_embedding(
+    return await openai_embed(
         texts,
         model=EMBEDDING_MODEL,
     )