This commit intorduces src/compiler/rust crate, which will have
different modules that help to write a backend compiler in Rust.
Signed-off-by: Christian Gmeiner <cgmeiner@igalia.com>
Reviewed-by: Faith Ekstrand <faith.ekstrand@collabora.com>
Part-of: <https://gitlab.freedesktop.org/mesa/mesa/-/merge_requests/30443>
