Feature - Add support for GGUF spec to read necessary details directly from the model

[crimson-knight]

Right now Llamero requires that you add the prompt template details yourself.

Not a big deal, but those details are already present in the model. So, using the GGUF spec, we should add support to read the initial bytes from the file to get the necessary information for the chat template.

This would be an excellent convenience.

GGUF Spec for reference: https://github.com/ggerganov/ggml/blob/master/docs/gguf.md

[crimson-knight]

This is partially implemented allowing fetching of certain special tokens for the chat prompt.