missing gguf api

[Leikoe]

currently trying to add examples to this lib, specifically https://github.com/ggerganov/ggml/blob/master/examples/mnist/main-cnn.cpp

[KerfuffleV2]

Unfortunately, I haven't really kept this project up to date and there are quite a few ops that are missing. I will think about how to approach continuing with this stuff, I'm actually not so sure right now.

Please ping me if you don't hear back within a week. I'm pretty bad about following up on stuff so I need the reminder. :)

[Leikoe]

I'm currently adding it, I'll make a pr when done dw.
I'd be happy to get feedback on my poorly written code if you find the time to read it :D

[Leikoe]

also adding mnist example from ggml repo