Proposing To Add Naming Convention For GGUF files in documents

[mofosyne]

Merged in https://github.com/ggerganov/llama.cpp/issues/7165 in llama.cpp which also includes changes to how default filenames are generated.

However I wasn't too sure where to place the proposed "GGUF Naming Convention". I think I should place it in https://github.com/ggerganov/ggml/blob/master/docs/gguf.md but happy to hear otherwise.

In short the naming convention I want to document is <Model>-<Version>-<ExpertsCount>x<Parameters>-<Quantization>.gguf (details of the proposal in https://github.com/ggerganov/llama.cpp/pull/4858)