Update webpack config to build sass themes

webpack.dev.js

@@ -1,11 +1,26 @@
 const common = require('./webpack.common');
 const { merge } = require('webpack-merge');
 
+const THEMES = [
+    'appletv',
+    'blueradiance',
+    'dark',
+    'light',
+    'purplehaze',
+    'wmc'
+];
+
 module.exports = merge(common, {
     // In order for live reload to work we must use "web" as the target not "browserslist"
     target: process.env.WEBPACK_SERVE ? 'web' : 'browserslist',
     mode: 'development',
-    entry: { 'main.jellyfin': './index.jsx' },
+    entry: {
+        'main.jellyfin': './index.jsx',
+        ...THEMES.reduce((acc, theme) => {
+            acc[`themes/${theme}`] = `./themes/${theme}/theme.scss`;
+            return acc;
+        }, {})
+    },
     devtool: 'eval-cheap-module-source-map',
     module: {
         rules: [