convert : improve Mistral models integration (#14737)
* Improve Mistral models integration with llama.cpp
* Revert changes and fix gguf
* Revert change
* refactor convert_mistral_to_gguf.py in convert_hf_to_gguf.py
* Revert collateral
* Rename model name
* refactor
* revert
* remove duplicate
* Remove duplication code
* Fixes
* Fix flake issues
* Apply comments
* Apply comments
* Apply comments
* Fix remote
* add default chat template
* Revert
* nit
