[ONNX] Support huggingface BART to ONNX (#12779)
Add BART into transformer support, specificalyy for
`BartForConditionalGeneration`
**Motivation and Context**
- fixes #11210
Currently, the custom op beam search is not working in nightly, this PR
should be run with a [custom
commit](https://github.com/microsoft/onnxruntime/commit/10f3d46d922809986e530dc5f9765fbabe7cb342)
