refactor: The first refactored version for sdk release (#907)

Co-authored-by: chengfangyin2 <chengfangyin3@jd.com>

examples/sdk/simple_sdk_llm_example.py

@@ -0,0 +1,18 @@
+import asyncio
+from dbgpt.core.awel import DAG
+from dbgpt.core import BaseOutputParser, OpenAILLM, RequestBuildOperator, PromptTemplate
+
+with DAG("simple_sdk_llm_example_dag") as dag:
+    prompt = PromptTemplate.from_template(
+        "Write a SQL of {dialect} to query all data of {table_name}."
+    )
+    req_builder = RequestBuildOperator(model="gpt-3.5-turbo")
+    llm = OpenAILLM()
+    out_parser = BaseOutputParser()
+    prompt >> req_builder >> llm >> out_parser
+
+if __name__ == "__main__":
+    output = asyncio.run(
+        out_parser.call(call_data={"data": {"dialect": "mysql", "table_name": "user"}})
+    )
+    print(f"output: \n\n{output}")