Review CSS preprocessor

[peterpeterparker]

We should review the CSS preprocessor and the way we imports CSS. This might requires some changes in gix-cmp bundles.

That way we can maybe also migrate from svelte-preprocess to @sveltejs/vite-plugin-svelte.

Stacktrace:

vite v5.0.10 building for production...
transforming (1) .svelte-kit/generated/client-optimized/app.js08:49:48 [vite-plugin-svelte] /Users/daviddalbusco/projects/dfinity/nns-dapp/frontend/src/routes/+layout.svelte svelte.preprocess depends on more than 10 external files which can cause slow builds and poor DX, try to reduce them. Found: /Users/daviddalbusco/projects/dfinity/nns-dapp/frontend/node_modules/@dfinity/gix-components/dist/styles/global.scss, /Users/daviddalbusco/projects/dfinity/nns-dapp/frontend/node_modules/@dfinity/gix-components/dist/styles/global/colors.scss, /Users/daviddalbusco/projects/dfinity/nns-dapp/frontend/node_modules/@dfinity/gix-components/dist/styles/global/variables.scss, /Users/daviddalbusco/projects/dfinity/nns-dapp/frontend/node_modules/@dfinity/gix-components/dist/styles/mixins/_media.scss, /Users/daviddalbusco/projects/dfinity/nns-dapp/frontend/node_modules/@dfinity/gix-components/dist/styles/global/fonts.scss, /Users/daviddalbusco/projects/dfinity/nns-dapp/frontend/node_modules/@dfinity/gix-components/dist/styles/mixins/_fonts.scss, /Users/daviddalbusco/projects/dfinity/nns-dapp/frontend/node_modules/@dfinity/gix-components/dist/styles/global/theme.scss, /Users/daviddalbusco/projects/dfinity/nns-dapp/frontend/node_modules/@dfinity/gix-components/dist/styles/global/layout.scss, /Users/daviddalbusco/projects/dfinity/nns-dapp/frontend/node_modules/@dfinity/gix-components/dist/styles/mixins/_display.scss, /Users/daviddalbusco/projects/dfinity/nns-dapp/frontend/node_modules/@dfinity/gix-components/dist/styles/mixins/_layout.scss, /Users/daviddalbusco/projects/dfinity/nns-dapp/frontend/node_modules/@dfinity/gix-components/dist/styles/global/button.scss, /Users/daviddalbusco/projects/dfinity/nns-dapp/frontend/node_modules/@dfinity/gix-components/dist/styles/mixins/_effect.scss, /Users/daviddalbusco/projects/dfinity/nns-dapp/frontend/node_modules/@dfinity/gix-components/dist/styles/global/link.scss, /Users/daviddalbusco/projects/dfinity/nns-dapp/frontend/node_modules/@dfinity/gix-components/dist/styles/global/tag.scss, /Users/daviddalbusco/projects/dfinity/nns-dapp/frontend/node_modules/@dfinity/gix-components/dist/styles/global/modal.scss, /Users/daviddalbusco/projects/dfinity/nns-dapp/frontend/node_modules/@dfinity/gix-components/dist/styles/global/grid.scss, /Users/daviddalbusco/projects/dfinity/nns-dapp/frontend/node_modules/@dfinity/gix-components/dist/styles/global/utility-classes.scss, /Users/daviddalbusco/projects/dfinity/nns-dapp/frontend/node_modules/@dfinity/gix-components/dist/styles/mixins/_content.scss, /Users/daviddalbusco/projects/dfinity/nns-dapp/frontend/node_modules/@dfinity/gix-components/dist/styles/global/blockquote.scss, /Users/daviddalbusco/projects/dfinity/nns-dapp/frontend/node_modules/@dfinity/gix-components/dist/styles/global/scrollbar.scss, /Users/daviddalbusco/projects/dfinity/nns-dapp/frontend/node_modules/@dfinity/gix-components/dist/styles/global/menu.scss, /Users/daviddalbusco/projects/dfinity/nns-dapp/frontend/node_modules/@dfinity/gix-components/dist/styles/global/selection.scss, /Users/daviddalbusco/projects/dfinity/nns-dapp/frontend/node_modules/@dfinity/gix-components/dist/styles/global/text.scss, /Users/daviddalbusco/projects/dfinity/nns-dapp/frontend/node_modules/@dfinity/gix-components/dist/styles/themes/dark.scss, /Users/daviddalbusco/projects/dfinity/nns-dapp/frontend/node_modules/@dfinity/gix-components/dist/styles/themes/light.scss, /Users/daviddalbusco/projects/dfinity/nns-dapp/frontend/src/lib/themes/legacy.scss, /Users/daviddalbusco/projects/dfinity/nns-dapp/frontend/src/lib/themes/global.scss, /Users/daviddalbusco/projects/dfinity/nns-dapp/frontend/src/lib/themes/variables.scss