support gpt-4o (#773)

### What problem does this PR solve?
#771 

### Type of change

- [x] New Feature (non-breaking change which adds functionality)

api/settings.py

@@ -86,6 +86,12 @@ default_llm = {
         "embedding_model": "",
         "image2text_model": "",
         "asr_model": "",
+    },
+    "DeepSeek": {
+        "chat_model": "deepseek-chat",
+        "embedding_model": "BAAI/bge-large-zh-v1.5",
+        "image2text_model": "",
+        "asr_model": "",
     }
 }
 LLM = get_base_config("user_default_llm", {})