GitLab

* move generation_*.py src files into generation/*.py

* populate generation.__init__ with lazy loading

* move imports and references from generation.xxx.object to generation.object

* add_ernie

* remove Tokenizer in ernie

* polish code

* format code style

* polish code

* fix style

* update doc

* make fix-copies

* change model name

* change model name

* fix dependency

* add more copied from

* rename ErnieLMHeadModel to ErnieForCausalLM
do not expose ErnieLayer
update doc

* fix

* make style

* polish code

* polish code

* fix

* fix

* fix

* fix

* fix

* final fix
Co-authored-by: ydshieh <ydshieh@users.noreply.github.com>