* add ppyoloe distill with soft loss and feature loss

* refine distill codes

* fix configs and docs

* clean codes

* merge cam, fix export

* add CWD distill code

* fix type

* fix bugs

* add retinanet teacher yml

* fix comments

* add code

* add ld-vlr

* refractor code

* refine code

* add doc

* refine details

* refine doc

* update download url

* rename config file for ci

* rename config file in README for CI

* add FGD distill code

* add yolov3 PrunerQAT joint compression strategy

* update readme

* unstructured prune for picodet

* update slim models and benchmark

* add Distill model
* add distill+prune

* add dygraph quant

* add prune dygraph, test=dygraph

* fix slim readme and prune

Merge dygraph branch into master branch.
Co-authored-by: NFDInSky <48318485+FDInSky@users.noreply.github.com>
Co-authored-by: Nsunxl1988 <47514455+sunxl1988@users.noreply.github.com>
Co-authored-by: Nwangguanzhong <jerrywgz@126.com>
Co-authored-by: Nwangxinxin08 <69842442+wangxinxin08@users.noreply.github.com>
Co-authored-by: Nwanghuancoder <wanghuancoder@163.com>
Co-authored-by: Ncnn <liuhui29@baidu.com>
Co-authored-by: NGuanghua Yu <742925032@qq.com>
Co-authored-by: NKaipeng Deng <dengkaipeng@baidu.com>
Co-authored-by: Nroot <root@bjyz-sys-gpu-kongming0.bjyz.baidu.com>

* Rename object_detection to PaddleDetection
* Small fix for doc