* feat: add BART example

* refactor: rm model_type

* style: optimize params name stype

* refactor: rm fluid api and correct equality judgment

* docs: add docs

* docs: update docs.

* feat: add jit

* docs: update docs

* fix: GELU change to approximate

* fix: add gelu judgement

* fix: update layer.activation

* refactor: update amp scaler usage

* docs: update docs

* docs: update docs for FasterBART

* docs: update docs for FasterBART

Co-authored-by: Zeyu Chen <chenzeyu01@baidu.com>