Improve model chat template handling by parsing out the end of output token automatically

[crimson-knight]

Models use special tokens to designate boundaries within prompts. Most models have a special "end of generation" token that they use when returning the results.

In llama models this is <|eot_id|>, and must be specified on the model class like follows:

model = Llamero::BaseModel.new(model_name: "meta-llama-3-8b-instruct-Q6_K.gguf", chat_template_end_of_generation_token: "<|eot_id|>")

Without this specification, the structured response will fail to parse. It's also inconvenient to have to remember to find this and configure it on the model.