* [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>

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

* fix config dependence & fix python 3.8/3.9 install

* add Distill model
* add distill+prune

* remove load_static_weights

* add VisualDL and save best_model

* add VisualDLWriter callback

* add blazeface & update rcnn modelzoo

* remove condition num_priors

* eval in train

* add ppyolo in dygraph

* fix bugs

* modify configs

* polish docs, modify ema and add configs

* modify link of model

* fix bugs in ema

* modify code according to review

* modify minicoco configs

* ppdet installable