Add Llama2 resources
Author: wonhyeongseo
Pull request: yes

Co-authored-by: @jungnerd @kihoon71 

# What does this PR do?

<!--
Congratulations! You've made it this far! You're not quite done yet though.

Once merged, your PR is going to appear in the release notes with the title you set, so make sure it's a great title that fully reflects the extent of your awesome contribution.

Then, please replace this with a description of the change and which issue is fixed (if applicable). Please also include relevant motivation and context. List any dependencies (if any) that are required for this change.

Once you're done, someone will review your PR shortly (see the section "Who can review?" below to tag some potential reviewers). They may suggest changes to make the code even better. If no one reviewed your PR after a week has passed, don't hesitate to post a new comment @-mentioning the same persons---sometimes notifications get lost.
-->

<!-- Remove if not applicable -->

Adds resources of Llama2 according to [this issue](https://github.com/huggingface/transformers/issues/20055).
This PR serves as an example to our OSSCA mentees who will contribute more models.

Part of #20055


## Before submitting
- [x] This PR fixes a typo or improves the docs (you can dismiss the other checks if that's the case).
- [x] Did you read the [contributor guideline](https://github.com/huggingface/transformers/blob/main/CONTRIBUTING.md#start-contributing-pull-requests),
      Pull Request section?
- [x] Was this discussed/approved via a Github issue or the [forum](https://discuss.huggingface.co/)? Please add a link
      to it if that's the case.
- [x] Did you make sure to update the documentation with your changes? Here are the
      [documentation guidelines](https://github.com/huggingface/transformers/tree/main/docs), and
      [here are tips on formatting docstrings](https://github.com/huggingface/transformers/tree/main/docs#writing-source-documentation).
- [ ] Did you write any new necessary tests?


## Who can review?

@stevhliu, may you please review this PR?

<!-- Your PR will be replied to more quickly if you can figure out the right person to tag with @

 If you know how to use git blame, that is the easiest way, otherwise, here is a rough guide of **who to tag**.
 Please tag fewer than 3 people.

Models:

- text models: @ArthurZucker and @younesbelkada
- vision models: @amyeroberts
- speech models: @sanchit-gandhi
- graph models: @clefourrier

Library:

- flax: @sanchit-gandhi
- generate: @gante
- pipelines: @Narsil
- tensorflow: @gante and @Rocketknight1
- tokenizers: @ArthurZucker
- trainer: @sgugger

Integrations:

- deepspeed: HF Trainer/Accelerate: @pacman100
- ray/raytune: @richardliaw, @amogkam

Documentation: @sgugger, @stevhliu and @MKhalusova

HF projects:

- accelerate: [different repo](https://github.com/huggingface/accelerate)
- datasets: [different repo](https://github.com/huggingface/datasets)
- diffusers: [different repo](https://github.com/huggingface/diffusers)
- rust tokenizers: [different repo](https://github.com/huggingface/tokenizers)

Maintained examples (not research project or legacy):

- Flax: @sanchit-gandhi
- PyTorch: @sgugger
- TensorFlow: @Rocketknight1

 -->


Comments:
The docs for this PR live [here](https://moon-ci-docs.huggingface.co/docs/transformers/pr_25531). All of your documentation changes will be reflected on that endpoint.

Hello everyone,

We've been working on organizing resources related to LLaMA2, and we've noticed that many of the resources intersect category-wise. We're trying to ensure that the documentation is intuitive and helpful for users. Could anyone provide suggestions or best practices on how to best arrange these resources?

Additionally, after conducting a full-text search on the repository, we couldn't locate any notebooks specifically related to LLaMA2. If anyone is aware of such notebooks or has worked on one, could you kindly point us in the right direction?

Thank you in advance for your assistance!

Best regards,
@wonhyeongseo and @jungnerd

There are quite a few ressources that are indeed not properly linked. 
Here is one notebook: https://colab.research.google.com/drive/1PEQyJO1-f6j0S_XJ8DV50NkpzasXkrzd?usp=sharing%E2%80%A6 that has been shared + updated by a contributor! 


Thank you for the pointer @ArthurZucker! With your guidance, we found googling `site:https://colab.research.google.com transformers llama2` to be quite effective and useful.

We have a couple of questions:
- Would it be okay to add Llama2 to the [text-generation script](https://github.com/huggingface/transformers/blob/36f183ebab1261b388739d628aaa0b4150068df0/examples/pytorch/text-generation/run_generation.py#L40) and update the [llm tutorial example](https://github.com/huggingface/transformers/blob/36f183ebab1261b388739d628aaa0b4150068df0/docs/source/en/llm_tutorial.md?plain=1#L77) to Llama2? (I feel that since llama2 is still gated, we cannot at this time)
- How would you like us to treat [spaces like this one](https://huggingface.co/TheBloke/llama-2-7B-Guanaco-QLoRA-GPTQ) for the resource section?
- Would it be ok to add LLaMA resources on top of Llama2 as they are the [same family like GPT](https://github.com/huggingface/transformers/pull/20084#pullrequestreview-1179625719)? (cc. @stevhliu )
  > Nice, thank you for adding those. Now you just have a few more to go! 😁
  > 
  > Take a look at the [OpenAI GPT2 resources page](https://huggingface.co/docs/transformers/main/en/model_doc/gpt2#resources) and feel free to add over whatever is missing here since the usage for OpenAI GPT is practically the same.

We will soon cover more models that are "mainstream" in Korea, translate the docs and contribute localized blogs and notebooks. Sorry for being so late on schedule.
  
Thank you so much for your friendly and honest guidance, hope we can have a call sometime.

Best regards,
Won

May you please review this PR, @stevhliu ? Thanks a ton for your help!

> Awesome, once we fix the tiny typo we're ready to merge!

Done and dusted. Thank you so much for your help @stevhliu ! Looking forward to our Q&A session!!