Add two new model in zoo

Add transformer and localformer (SLGT) models for time series prediction in finance in the Quant Model Zoo.

Author: yingtaoluo

README.md

@@ -291,6 +291,8 @@ Here is a list of models built on `Qlib`.
 - [TabNet based on pytorch (Sercan O. Arik, et al. AAAI 2019)](qlib/contrib/model/pytorch_tabnet.py)
 - [DoubleEnsemble based on LightGBM (Chuheng Zhang, et al. ICDM 2020)](qlib/contrib/model/double_ensemble.py)
 - [TCTS based on pytorch (Xueqing Wu, et al. ICML 2021)](qlib/contrib/model/pytorch_tcts.py)
+- [Transformer based on pytorch (Ashish Vaswani, et al. NeurIPS 2017)](qlib/contrib/model/pytorch_transformer.py)
+- [TCTS based on pytorch (Juyong Jiang, et al.)](qlib/contrib/model/pytorch_localformer.py)
 
 Your PR of new Quant models is highly welcomed.