Build improvements (#649)

* Improve PWA capabilities

* Invert background_color theme logic

* Revert build changes

* Revert "Revert build changes"

This reverts commit 1ab640fda1.

* update

* revert svelte component changes

rollup.config.mjs

@@ -0,0 +1,37 @@
+import svelte from 'rollup-plugin-svelte';
+import resolve from '@rollup/plugin-node-resolve';
+import terser from '@rollup/plugin-terser';
+
+const production = !process.env.ROLLUP_WATCH;
+
+export default {
+  input: 'bookmarks/frontend/index.js',
+  output: {
+    sourcemap: true,
+    format: 'iife',
+    name: 'linkding',
+    // Generate bundle in static folder to that it is picked up by Django static files finder
+    file: 'bookmarks/static/bundle.js',
+  },
+  plugins: [
+    svelte({
+      emitCss: false,
+    }),
+
+    // If you have external dependencies installed from
+    // npm, you'll most likely need these plugins. In
+    // some cases you'll need additional configuration —
+    // consult the documentation for details:
+    // https://github.com/rollup/rollup-plugin-commonjs
+    resolve({
+      browser: true,
+    }),
+
+    // If we're building for production (npm run build
+    // instead of npm run dev), minify
+    production && terser(),
+  ],
+  watch: {
+    clearScreen: false,
+  },
+};