llama : add grok-1 support (#6204)

* Add support for Grok model architecture

* Revert convert-hf-to-gguf to default options

* Fixed f_norm_rms_eps bug

* Fix whitespaces

* llama : fix grok rope type

* llama : minor

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Co-authored-by: Georgi Gerganov <ggerganov@gmail.com>