Modify file structure to separate python and cpp code (#223)

Modify code structure

python/fastdeploy/vision/detection/__init__.py

@@ -0,0 +1,26 @@
+# Copyright (c) 2022 PaddlePaddle Authors. All Rights Reserved.
+#
+# Licensed under the Apache License, Version 2.0 (the "License");
+# you may not use this file except in compliance with the License.
+# You may obtain a copy of the License at
+#
+#     http://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing, software
+# distributed under the License is distributed on an "AS IS" BASIS,
+# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+# See the License for the specific language governing permissions and
+# limitations under the License.
+
+from __future__ import absolute_import
+from .contrib.yolov7 import YOLOv7
+from .contrib.yolor import YOLOR
+from .contrib.scaled_yolov4 import ScaledYOLOv4
+from .contrib.nanodet_plus import NanoDetPlus
+from .contrib.yolox import YOLOX
+from .contrib.yolov5 import YOLOv5
+from .contrib.yolov5lite import YOLOv5Lite
+from .contrib.yolov6 import YOLOv6
+from .contrib.yolov7end2end_trt import YOLOv7End2EndTRT
+from .contrib.yolov7end2end_ort import YOLOv7End2EndORT
+from .ppdet import PPYOLOE, PPYOLO, PPYOLOv2, PaddleYOLOX, PicoDet, FasterRCNN, YOLOv3, MaskRCNN