feat 新增接口描述 docs页面 ，新增S3 图片get upload 操作，整理代码

fix

app/service/design/items/pipelines/split.py

@@ -1,11 +1,12 @@
 import logging
+
 import cv2
 import numpy as np
+from PIL import Image
 from cv2 import cvtColor, COLOR_BGR2RGBA
 
 from app.service.utils.generate_uuid import generate_uuid
 from ..builder import PIPELINES
-from PIL import Image
 from ...utils.conversion_image import rgb_to_rgba
 from ...utils.upload_image import upload_png_mask