chore: Speed up site build preview speed

[zombieJ]

[中文版模板 / Chinese template]

🤔 This is a ...

• New feature
• Bug fix
• Site / documentation update
• Demo update
• Component style update
• TypeScript definition update
• Bundle size optimization
• Performance optimization
• Enhancement feature
• Internationalization
• Refactoring
• Code style optimization
• Test Case
• Branch merge
• Other (about what?)

🔗 Related issue link

💡 Background and solution

主题文件通过 webpack 编译后速度慢了很多，做了一些提速操作（M1 测试数据）：

1. 将 webpack 一些库抽离以提升 js 编译速度，一份主题 css 大概从 5+m 提速到 1m
2. 标准 site 编译通过 env 设置 SITE_ENV 为 development 模式，从 9m 提速到 3+m

[github-actions]

[codecov]

Codecov Report

Merging #33045 (ea5bb0f) into master (6f837e0) will not change coverage.
The diff coverage is n/a.

@@            Coverage Diff             @@
##            master    #33045    +/-   ##
==========================================
  Coverage   100.00%   100.00%            
==========================================
  Files          414       414            
  Lines         7675      7813   +138     
  Branches      2214      2253    +39     
==========================================
+ Hits          7675      7813   +138     

Impacted Files	Coverage Δ
components/list/index.tsx	100.00% <0.00%> (ø)
components/menu/index.tsx	100.00% <0.00%> (ø)
components/layout/Sider.tsx	100.00% <0.00%> (ø)
components/menu/SubMenu.tsx	100.00% <0.00%> (ø)
components/anchor/Anchor.tsx	100.00% <0.00%> (ø)
components/form/FormList.tsx	100.00% <0.00%> (ø)
components/layout/layout.tsx	100.00% <0.00%> (ø)
components/checkbox/Group.tsx	100.00% <0.00%> (ø)
components/descriptions/index.tsx	100.00% <0.00%> (ø)
components/form/FormItemInput.tsx	100.00% <0.00%> (ø)
... and 4 more

---

Continue to review full report at Codecov.

Legend - Click here to learn more
Δ = absolute <relative> (impact), ø = not affected, ? = missing data
Powered by Codecov. Last update 6f837e0...ea5bb0f. Read the comment docs.

[github-actions]

Size Change: 0 B

Total Size: 923 kB

ℹ️ View Unchanged

Filename	Size
./dist/antd-with-locales.min.js	356 kB
./dist/antd.compact.min.css	65.1 kB
./dist/antd.dark.min.css	66.5 kB
./dist/antd.min.css	65.1 kB
./dist/antd.min.js	305 kB
./dist/antd.variable.min.css	65.8 kB

_{compressed-size-action}

[zombieJ]

CI 数据：

• Origin ~ 39m: https://github.com/ant-design/ant-design/runs/4329813867?check_suite_focus=true
• Current ~ 22m: https://github.com/ant-design/ant-design/runs/4331048626?check_suite_focus=true