Upgrade webpack, remove service worker, other small optimizations

WebConfigGenerator/src/app.js

@@ -0,0 +1,17 @@
+import Vue from 'vue';
+import VueI18n from 'vue-i18n';
+
+import App from './App.vue';
+import i18nSettings from './i18n.js';
+import router from './router.js';
+
+Vue.use(VueI18n);
+const i18n = new VueI18n(i18nSettings);
+
+new Vue({
+    el: '#app',
+    router,
+    i18n,
+    template: '<App/>',
+    components: { App }
+});