Rollup production build in Vue3

[joseacabaneros]

• Migrate scss to css, scoped when only necessary, and clean up. CSS nesting and scoped doesn't generate a right CSS code. Flatten class selectors and use CSS to avoid preprocessors
• Use @vitejs/plugin-vue instead of deprecated rollup-plugin-vue
• Use a simple custom CSS injector build/tools/inject-css.js in vue-plugin-styles
• Simplify the build.ts content
• Make apiDocumentation plugin work in the build process 🥳

[joseacabaneros]

There is an issue with no-scoped styles in layout. They are no-scoped and have shared class names, so styles of all layouts are applied to the same. It can be replicated in serve with Vite.
WIP in a workaround for layouts.