Implement tf big bird port
# What does this PR do?
Solves #19430 by implementing BigBird in Tensorflow

I had an earlier demo PR up, but this one will be the main PR I use to hopefully get this merged in once it's all working :)


## 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?
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      to it if that's the case.
- [ ] 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?


## Who can review?

Tagging @Rocketknight1 as they were kind enough to help me with this already with an issue I was running into with outputting attention weights using strided slices, but would appreciate any inputs from anyone!

Most of the tests are working as expected now, I am still running into a couple issues with two or three tests, that I need to look into:

1) Issue with TFAutoModel in test not raising a `ValueError` in one of the tests for mismatching sizes (but the `TFAutoModelForSequenceClassification` is working in this test 🤔).
2) Issue persisting and loading (`save_load` and `keras_load` tests aren't working fully yet)

I'm going to try and work on this some more this weekend, if anyone has any insights I'd love to know :D
The docs for this PR live [here](https://moon-ci-docs.huggingface.co/docs/transformers/pr_20052). All of your documentation changes will be reflected on that endpoint.<|||||>This issue has been automatically marked as stale because it has not had recent activity. If you think this still needs to be addressed please comment on this thread.

Please note that issues that do not follow the [contributing guidelines](https://github.com/huggingface/transformers/blob/main/CONTRIBUTING.md) are likely to be ignored.