Can you please support context parallel?

[DZ9]

Nemo suport context parallel in nature, with the adaption in [MegatronGPTModel] (https://github.com/NVIDIA/NeMo/blob/96187eac848ebf02c56e9fc658a57a500a56a842/nemo/collections/nlp/models/language_modeling/megatron_gpt_model.py#L1039) get_forward_output_and_loss_func method.

I found all dpo, ppo and rm model inherit MegatronGPTModel but rewrite the get_forward_output_and_loss_func method without the adaption of context parallel, can you please add the support because it is efficient for long context training.