* add mainkd for ppyoloe distill

* refine code style

* add ppyoloe semi-det base codes

* fix configs

* fix head distill loss

* add more semi_det configs and fix doc, test=document_fix

* add contrast_loss config, test=document_fix

* add ppyoloe distill with soft loss and feature loss

* refine distill codes

* fix configs and docs

* clean codes

* merge cam, fix export

* fix slice infer one image save_results (#7654)

* Support GradCAM Cascade_rcnn forward bugfix

* code style fix

* BBoxCAM class name fix

* Add gradcam tutorial and demo

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Co-authored-by: NFeng Ni <nemonameless@qq.com>

* add ppyoloe plus tiny with aux_head

* fix ppyoloe tiny training

* fix ppyoloe+ tiny p2 model

* add ppyoloe t p2 model

* fix sm_use for ppyoloe_head and output for box_dis

* fix pos_embed of training

* [smdet] add tal_cr and custompan with transfomer, add box_distribution to pred reg_max, test=document_fix

* add tal_cr

cast dtype in load_pretrain_weight

* clean fluid

* mv static to legacy

* remove yolo box

* revert legacy dir

* revert static link

* update in_dynamic_mode

* clean iou_similarity, collect_fpn_proposals, bipartite_match

* add nms trt support

* add check version code

* fix bugs

* Add PP-YOLOE yaml

* rename PP-YOLOE

* Add exclude_nms in ppyoloe_head

* rename pretrain_weights

* [ppyolov3] add ppyolov3 base code

* add ppyolov3 s/m/x

* modify ema

* modify code to convert onnx successfully

* support arbitrary shape

* update config to use amp default

* refine ppyolo_head code

* modify reparameter code

* refine act layer

* adapter pico_head and tood_head code

* remove ppyolov3 yaml

* fix codestyle
Co-authored-by: Nwangxinxin08 <wangxinxin08@baidu.com>