Replace Node Sass (node-sass) with Dart Sass (sass) in JavaScript

• plentycode/sass-export#69
• !2175 (closed): Update sass-export to 2.1.0 to partially migrate to sass
• !2846 (merged): Update sass-export to 2.0.1 to partially migrate to sass
• !2176 (merged): Replace node-sass with sass

Part of &5923 (closed)