Update 2.0 Save/Load API names/arguments/doc examples#27138

Merged

chenwhql merged 3 commits intoPaddlePaddle:release/2.0-betafrom

chenwhql:release2.0-beta/save_load_configs_name_change

Sep 8, 2020

Commits on Sep 7, 2020

Update set_dict method name & add aliases (#26700)
chenwhql
committed
Support load state dict form `inference model` format save result (#26718)
chenwhql
committed
Change jit.save/load configs to config & update code examples (#27056)
chenwhql
committed