GitLab

* Move JSON grammar -> regex grammar conversion to the router

This change moves the JSON grammar -> regex grammar conversion to the
router by adding a dependency on the `outlines-core` Rust crate. In
contrast to the Python implementation, the conversions are not LRU-cached
since they seem to be fast enough:

simple schema           time:   [5.8293 µs 5.8307 µs 5.8320 µs]
                        change: [-13.166% -12.884% -12.641%] (p = 0.00 < 0.05)
                        Performance has improved.

complex schema          time:   [14.875 µs 14.881 µs 14.887 µs]
                        change: [-2.1637% -1.9914% -1.7852%] (p = 0.00 < 0.05)
                        Performance has improved.

Using the schemas from:
https://github.com/dottxt-ai/outlines-core/blob/main/benchmarks/bench_json_schema.py