Add support for `PaliGemma`

[awsaf49]

Keras desperately needs a vision language LLM model. As PaliGemma has been released, I think it might be the perfect time we add this model to KerasNLP or KerasCV.

Ref:

• Kaggle Models: https://www.kaggle.com/models/google/paligemma
• Docs: https://ai.google.dev/gemma/docs/paligemma