Support Llama 3.2 conversion (text models) (#33778)

* Support Llama 3.2 conversion (text models)

Co-authored-by: Omar Sanseviero <[email protected]>

* Fix rope factor

* Update chat template

Initialize from a well-known template.
The guidance is that the changes should be applied to 3.1 models as
well.

* Remove import

* Support Llama Guard 3 conversion

* Tokenizer details

* Fix eos added token in base models

* Fix generation config for base models

* Specify revision for known tokenizers

* Style

* Reuse chat templates for older models

* Improve error when converting tokenizer < Llama 3

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Co-authored-by: Omar Sanseviero <[email protected]>