Support for GBNF Grammars

[benbot]

Llama.cpp has had support for BNF style grammars for a while, but I don't see how I can use them with these bindings.

Is there a way?

If not, is there a good starting place for hooking them up? I could take a whack at trying to get it set up, but I don't know a lot about cpp <-> rust bindings

[Szetty]

We also need this, and I have tried to add the support for it, but it is not working as expected, so maybe I am not calling it when it should be called, so probably we need someone who knows this integration better

[anttikallonentuni]

I would also be interested in this. Or similar way to restrict the output to a specific format using the rust bindings.