The build in loaders:
sass: https://github.com/utooland/utoo/blob/next/crates/pack-core/src/shared/webpack_rules/sass.rs
less: https://github.com/utooland/utoo/blob/next/crates/pack-core/src/shared/webpack_rules/less.rs
style-loader: https://github.com/utooland/utoo/blob/next/crates/pack-core/src/shared/webpack_rules/style_loader.rs

now can be configured by module.rules, don't need the rust wrapper anymore.