[Feature] Add test time augmentation base model. (#538)

* First commit

* add BaseTestTimeAugModel

* Add unit test

* move loop logic to test_step

* fix ddp test

* rename model to module

* optim __init__

* Fix as comment

* Fix as comment

* make val_step should not be called

* make tta do not inherit base model

* Fix unit test

* Enhance docstring

* Fix as comment

* Fix as comment

* minor refine

* minor refine

* minor refine

* fix unit test

* minor refine

* minor refine

* minor refine

* minor refine

* minor refine

* minor refine

* fix unit test