llama : add llama-3 chat template (#6751)

* Added llama-3 chat template

* Update llama.cpp

Co-authored-by: Samuel Tallet <36248671+SamuelTallet@users.noreply.github.com>

* Update llama.cpp

Co-authored-by: Samuel Tallet <36248671+SamuelTallet@users.noreply.github.com>

* Update tests/test-chat-template.cpp

Co-authored-by: Samuel Tallet <36248671+SamuelTallet@users.noreply.github.com>

* Added EOS stop sequence according to https://github.com/ggerganov/llama.cpp/pull/6751#issuecomment-2065602862

* Removed adding of BOS token before first message

* Removed bos token from expected output from llama-3

* Update tests/test-chat-template.cpp

Co-authored-by: Rene Leonhardt <65483435+reneleonhardt@users.noreply.github.com>

* Update tests/test-chat-template.cpp

Co-authored-by: Rene Leonhardt <65483435+reneleonhardt@users.noreply.github.com>

* Added <|end_of_text|> as another stop token

* Reverted last change of adding the end_of_text stop word for llama 3

---------

Co-authored-by: Wouter Tichelaar <tichelaarw@spar.net>
Co-authored-by: Samuel Tallet <36248671+SamuelTallet@users.noreply.github.com>
Co-authored-by: Rene Leonhardt <65483435+reneleonhardt@users.noreply.github.com>
Co-authored-by: Georgi Gerganov <ggerganov@gmail.com>