Writing up a "Contributing" guide about candle

[LaurentMazare]

I'm not 100% sure what should be put in such a guide, hence its absence for now :)
To me, the best way for people to get involved is to start by using candle and writing the models that they care about - it would be great to see libraries emerge that use candle to build an equivalent to llama.cpp or whisper.cpp (we provide these in the main repo but the goal is not to be feature complete here but rather to show how candle can be used in such cases).
Besides this the model wishlist #1177 is a great place to find models that would be helpful to other people.
One thing that we're lacking at the moment is onboarding material for people writing new models, and this could certainly use some help. The "book" should certainly be revamped, or maybe even rewritten from scratch, and it would be great to have more tutorials and teaching material that describe how to convert some existing pytorch models to candle.

A list of starter issues would be good, things that aren't super high priority but would be welcome additions.

[tomsanbear]

Perfect, that sounds like a good idea with the book and improving rust docs on the operations as well 👍