* given inference model path, download model automatically

* encapsulate auto download model as a function

* given note that default model dir is download link

* change attr model download path to https://bj.bcebos.com/v1/paddledet/models/pipeline/PPLCNet_x1_0_person_attribute_945_infer.zip

* attribute docs update

* fix mtmct

* update docs

* fix pphuman cfg doc, test=document_fix

* fix doc, test=document_fix

* remove en readme doc, test=document_fix

* refactor doc, test=document_fix

* update yolox & yolov5, test=document_fix

* Update README_cn.md

* update doc, test=document_fix

* Update readme and pphuman readme

* Update README.md

* add data & customize, test=document_fix

* update readme

* Update README_cn.md

* Update README_cn.md

* add template, test=document_fix
Co-authored-by: NYixinKristy <576550767@qq.com>

* add_en_doc_for_pphuman, test=document_fix

* update link, test=document_fix

* add attr dataset link, test=document_fix

* correct link, test=document_fix

* Create README_en.md

* Update README_en.md

* add attr doc

* update attr intro