Merge commit '0150e56b' of https://github.com/tink2123/PaddleOCR into serving

split cpp inference

update joinus

New functions of PPOCRLabel release 

New functions: Open the dataset folder, image rotation, add shortcut key description, repair the direction shortcut key movement function under batch processing 

fix cpp

【SIG】增添打开当前正在标注的数据集文件夹

Update move box

rename bool to str2bool

update opencv version for py3.9

Update joinus.png

update ocr_rec_params for ci shell

Fix bugs

Test v7

去除部分冗余代码