[New Configs] Add new config file for ade20k and maskformer

The Configs file had been tested, all the training can be run properly and the inference result is same as result in this link

Training for maskformer_r50_d32_8xb2_160k_ade20k_512x512.py

Training for maskformer_r101_d32_8xb2_160k_ade20k_512x512.py

Training for maskformer_swin_s_upernet_8xb2_160k_ade20k_512x512.py

Training for maskformer_swin_t_upernet_8xb2_160k_ade20k_512x512.py

Inference result of maskformer_r50_d32_8xb2_160k_ade20k_512x512.py

Inference result of maskformer_r101_d32_8xb2_160k_ade20k_512x512.py

Inference result of maskformer_swin_s_upernet_8xb2_160k_ade20k_512x512.py

Inference result of maskformer_swin_t_upernet_8xb2_160k_ade20k_512x512.py