* add keypoint top-down cpp infer; total:5ms,pre:0.7ms,infer:3.8ms,post:0.01ms

* add dark_pose support

Revert "add keypoint top-down cpp infer; total:5ms,pre:0.7ms,infer:3.8ms,post:0.01ms (#4058)" (#4216)

This reverts commit 08619b4e.

* Update PicoDet adn GFl

* add --save_prediction_only support for TopDown KeyPoint Metric

* add a use case for save_prediction_only

* add python train time eval

* add mpii infer support

* add flops

Besides removing unnecessary imports, this also fixes the missing logger module in test_architectures.py within the static directory.

* add deepsort export model, reid infer

* fix jde_yolov3 metric

* fix deepsort deploy

* fix doc, clean code

* add mot deploy infer image, add run_benchmark

add dark deploy supported, mpii deploy supported;

* support --eval for s2anet

* add spine dataset and config yml for s2anet

* add doc for s2anet

* update doc

* fix typo, test=document_fix

* add some comments, and update import

* add mot score to txt results

* fix mot install typo

* add epoch for deepsort

* fix paddle no_grad

* deploy infer save image txt

* remove mot metric

* lazy import motmetrics

* jde fairmot export and video python infer

* bs>1 for YOLO

* update slim models and benchmark

* fix config dependence & fix python 3.8/3.9 install

* add fairmot

* rename pretrain_weights

* add comments; reuse focal loss and convnorm

* update comments

* fix eval snapshot_epoch

* add config for jde and deepsort, add engine metric tools

* add mot_metrics

* fix configs engine and others

* fix configs others

* move configs

* fix ap_per_class, fix doc

* fix test_mode, seqs

* fix test_mode to metric

* fix JDE arch metric

* clean requirement

* add to requirement

* s2anet fix export and deploy

* remove redundant code

* fix cpp for s2anet deploy

* fix bug of get_categories

* rename poly_to_rbox to poly2rbox

* add some comment for function

* Add BottomUp HigherHRNet for pose.
* reverse xtcocotools to pycocotools

* Add S2ANet model for Oriented Object Detection.

* add Distill model
* add distill+prune

* refine trainer

* unity weights