add configs for vit backbone plus decode_heads (#520)

* add config

* add cityscapes config

* add default value to docstring

* fix lint

* add deit-s and deit-b

* add readme

* add eps at norm_cfg

* add drop_path_rate experiment

* add deit case at init_weight

* add upernet result

* update result and add upernet 160k config

* update upernet result and fix settings

* Update iters number

* update result and delete some configs

* fix import error

* fix drop_path_rate

* update result and restore config

* update benchmark result

* remove cityscapes exp

* remove neck

* neck exp

* add more configs

* fix init error

* fix ffn setting

* update result

* update results

* update result

* update results and fill table

* delete or rename configs

* fix link delimiter

* rename configs and fix link

* rename neck to mln