docs: bard proxy usage

1.bard proxy usage.
2.quick deploy DBGPT by aliyun images.

docs/modules/llms.md

@@ -126,3 +126,11 @@ MODEL_SERVER=127.0.0.1:8000
 PROXY_API_KEY=sk-xxx
 PROXY_SERVER_URL={your-openai-proxy-server/v1/chat/completions}
 ```
+
+### 2. Bard Proxy
+- If your environment deploying DB-GPT has access to https://bard.google.com/, then modify the .env configuration file as below will work.
+```
+LLM_MODEL=bard_proxyllm
+MODEL_SERVER=127.0.0.1:8000
+BARD_PROXY_API_KEY={your-bard-key}
+```