feat: hoist compiler options builder to Compiler::builder

[h-a-n-a]

Summary

Hoisted the first level of CompilerOptions::builder to Compiler::builder to improve DX.

Updated:

let mut compiler = Compiler::builder()
    .context(Utf8Path::new(env!("CARGO_MANIFEST_DIR")).join("tests/fixtures/basic"))
    .entry("main", "./src/index.js")
    .build();

Checklist

• Tests updated (or not required).
• Documentation updated (or not required).

[netlify]

✅ Deploy Preview for rspack canceled.

Name	Link
🔨 Latest commit	ad0f447
🔍 Latest deploy log	https://app.netlify.com/sites/rspack/deploys/6788ce2fda4a2000086cef17

[codspeed-hq]

CodSpeed Performance Report

Merging #9020 will not alter performance

_{Comparing hoist-compiler-builder (ad0f447) with main (f9aa179)}

Summary

✅ 3 untouched benchmarks