[Feat] Llama new models

[Daggx]

In this pr we are :

• Removing old Llama models (llama2)
• Changing the prompt format so it can accept llama3 & llama 3.1. source : https://llama.meta.com/docs/model-cards-and-prompt-formats/meta-llama-3/

ps : we need to change the s3 region settings before we push it to master

new llama models are only availaible on us-west-2 (atm it uses us-east-1)