Duckduckgosearch (#1388)

### What problem does this PR solve?

#918 

Add components: Baidu, Duckduckgo

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

graph/component/__init__.py

@@ -10,6 +10,7 @@ from .message import Message, MessageParam
 from .rewrite import RewriteQuestion, RewriteQuestionParam
 from .keyword import KeywordExtract, KeywordExtractParam
 from .baidu import Baidu, BaiduParam
+from .duckduckgosearch import DuckDuckGoSearch, DuckDuckGoSearchParam
 
 
 def component_class(class_name):