Add Graph Baidusearch and dsl_example (#1378)

### What problem does this PR solve?

#918 

### Type of change

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

graph/component/__init__.py

@@ -8,6 +8,8 @@ from .switch import Switch, SwitchParam
 from .relevant import Relevant, RelevantParam
 from .message import Message, MessageParam
 from .rewrite import RewriteQuestion, RewriteQuestionParam
+from .keyword import KeywordExtract, KeywordExtractParam
+from .baidu import Baidu, BaiduParam
 
 
 def component_class(class_name):