Include the scripts for preprocessing OAST and unit tests for chat sft datasets
In this PR.

1. include scripts for preprocess OAST datasets.
2. annotate the datasets using reward model.
3. clean up the data for training.
4. include the unit tests to make sure the Chat SFT datasets produced expected masks. 
5. add support in the UI to run attribute condition generations.
6. add HF dataset as JSON dataset backend.