Add ConvNeXT V2
# What does this PR do?
Adds [ConvNeXT V2](https://arxiv.org/pdf/2301.00808.pdf) to transformers, including a backbone. ConvNeXT V2 features minimal changes to the `ConvNextLayer` and achieves an average 1% accuracy gain over ConvNext V1. Original repo is over [here](https://github.com/facebookresearch/ConvNeXt-V2).

- [X ] Upload ImageNet 1K fine-tuned models
- [x] Upload ImageNet 22K fine-tuned models
- [x] Update model cards
- [ ] Fix TF model bugs

## Before submitting
- [ ] 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?
- [ ] 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).
- [ X] Did you write any new necessary tests?

_The documentation is not available anymore as the PR was closed or merged._