Experiment with Rspack build (to benchmark)

[AlexeyMz]

No description provided.

[AlexeyMz]

Results

Bundle sizes with Rspack:

 178087 layout.worker.js
 455720 layout.worker.js.map
 442845 layout-sync.js
 491399 layout-sync.js.map
  18343 legacy-styles.js
  12709 legacy-styles.js.map
1632390 workspace.js
2894464 workspace.js.map

• Build time: ~30s on GitHub Actions, the same as with Webpack.
• Bundle size is almost exactly the same as with Webpack.