Support for GPT-Neo and GPT-J models

Is your feature request related to a problem? Please describe.
I see quite some GPT-2 implementations, but I am missing a GPT-Neo/GPT-J implementation. This is a variant of GPT-2 which is quite similar to GPT-2 in concept, but with much better results compared to GPT-2. Documentation about GPT-Neo can be found here: https://huggingface.co/docs/transformers/model_doc/gpt_neo

System information

• ONNX Runtime version (you are using): 1.11.0

Describe the solution you'd like
A demo that shows that GPT-Neo and GPT-J models can be used with ONNX to speed up huggingface models.

Describe alternatives you've considered
Since GPT-2 with LMhead outputs a similar output as GPTNeoForCausalLM, it should be possible to clone the demo. However, optimization will need to be done differently.

Additional context
I am one of the contributors behind KoboldAI, an OSS application that uses GPT-Neo and GPT-J models for creating short novels and text. Am looking for ways to optimize and speed up the models we distribute.