[PaddlePaddle Hackathon] Task 72: Add PAA

[gbstack]

PR types

New features

PR changes

APIs

Describe

Hi,

This PR add PAA (Probalistic Anchor Assignment) implementation

[CLAassistant]

Thank you for your submission! We really appreciate it. Like many open source projects, we ask that you all sign our Contributor License Agreement before we can accept your contribution.
12 out of 13 committers have signed the CLA.

✅ wangxinxin08
✅ heavengate
✅ lyuwenyu
✅ nemonameless
✅ YixinKristy
✅ ghostxsl
✅ zhiboniu
✅ jerrywgz
✅ liuhuiCNN
✅ yghstill
✅ gbstack
✅ will-jl944
❌ cnn

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[jerrywgz]

建议向develop分支提交pr，当前改动量太大了

[lyuwenyu]

你好 有模型训练的结果嘛

[gbstack]

你好 有模型训练的结果嘛

你好，目前还没有训练结果，我训练完之后发上来吧

[gbstack]

建议向develop分支提交pr，当前改动量太大了

好的