Switch to esbuild & NodeJS 18

- Replace Axios with `fetch` api
- Update dependencies

Signed-off-by: Knut Ahlers <knut@ahlers.me>

ci/build.mjs

@@ -0,0 +1,28 @@
+import { sassPlugin } from 'esbuild-sass-plugin'
+import vuePlugin from 'esbuild-vue'
+import esbuild from 'esbuild'
+
+esbuild.build({
+  assetNames: '[name]',
+  bundle: true,
+  define: {
+    'process.env.NODE_ENV': JSON.stringify(process.env.NODE_ENV || 'dev'),
+  },
+  entryPoints: ['src/main.js'],
+  loader: {
+    '.woff2': 'file',
+  },
+  minify: true,
+  outfile: 'frontend/app.js',
+  plugins: [
+    sassPlugin(),
+    vuePlugin(),
+  ],
+  target: [
+    'chrome87',
+    'edge87',
+    'es2020',
+    'firefox84',
+    'safari14',
+  ],
+})