new: Completed support for migrating images to Tencent Cloud COS

uploader.py

@@ -0,0 +1,13 @@
+from picbed.cos import cos_upload_img
+
+
+class Uploader:
+    def __init__(self):
+        pass
+
+    def upload_web_img(self, img_url, pic_bed):
+        if pic_bed == 'COS':
+            return cos_upload_img(img_url)
+        else:
+            print('Unsupported image hosting type')
+            exit(1)