fastdeploy support serving (#272)

* fd support serving

* fd support serving optimize dir

* optimize code

Co-authored-by: Jason <jiangjiajun@baidu.com>

python/fastdeploy/vision/__init__.py

@@ -22,4 +22,5 @@ from . import facedet
 from . import faceid
 from . import ocr
 from . import evaluation
+from .utils import fd_result_to_json
 from .visualize import *