* enable compile configurations to support torch.compile in Runner

* enable compilation in train, val and test

* fix as comments

* add docstring to illustrate usage

* minor refine error message

* add unittests

* fix ut skip

* add logging message to inform users

* compile `train_step`, `val_step`, `test_step` instead

* fix as comments

* revert to compile `train_step` only due to pt2 issue

* add documentation about torch.compile