* Update default xpu to ipex 2.1
* Update related install ut support correspondingly
* Add arc ut tests for both ipex 2.0 and 2.1
* Small fix
* Diable ipex 2.1 test for now as oneapi 2024.0 has not beed installed on the test machine
* Update document for default PyTorch 2.1
* Small fix
* Small fix
* Small doc fixes
* Small fixes