PaddleClas v2.2.0

1. Architecture
   1.1. ppcls backbones are now separated into two groups: legendary models and model zoo.
   1.2. Legendary models inherit from a new base class TheseusLayer, which allows stop at some point or even change architectures
2. Metric Learning
   2.1. Add a lot of metric learning functions, including gears, which can be inserted into arch , and losses.
   2.2. PaddleClas now support classification task and metric learning task using the same trainer. You only need switch different configs.
3. Vector Search
   3.1. Intergrate Mobius vector search algorithm.
4. Applications
   4.1. Add new applications: product recognition, logo recognition, car classification, car ReID and cartoon character recognition.
   4.2. Add new image recognition pipeline, which contains detection, feature extraction and vector search.
5. New models
   5.1. add LeViT、Twins、TNT、DLA、HarDNet、RedNet models