Frontend: Extract CSS imports into files (#94655)

* build(webpack): extract css imports into files including node_modules

* feat(webassets): add cssfiles to entrypoint assets for extracted css files

* feat(views): add entrypoint css link tags to html templates

* feat(webassets): set CDN prefix for CSS files

* test(webassets): trim down sample-assets-manifest, fix failing snapshot tests

* Update pkg/api/webassets/webassets_test.go

Co-authored-by: Marcus Efraimsson <marcus.efraimsson@gmail.com>

* build(webpack): remove css module loader

---------

Co-authored-by: Marcus Efraimsson <marcus.efraimsson@gmail.com>

scripts/webpack/sass.rule.js

@@ -5,8 +5,7 @@ const path = require('path');
 
 module.exports = function (options) {
   return {
-    test: /\.scss$/,
-    exclude: /node_modules/,
+    test: /\.(sa|sc|c)ss$/,
     use: [
       MiniCssExtractPlugin.loader,
       {

scripts/webpack/webpack.common.js

@@ -96,10 +96,6 @@ module.exports = {
           },
         ],
       },
-      {
-        test: /\.css$/,
-        use: ['style-loader', 'css-loader'],
-      },
       {
         test: /\.(svg|ico|jpg|jpeg|png|gif|eot|otf|webp|ttf|woff|woff2|cur|ani|pdf)(\?.*)?$/,
         type: 'asset/resource',