Fix issue caused by async plugin installation

src/plugins/translation.js

 import Polyglot from 'node-polyglot';
 
-const Translation = {}
-Translation.install = async function(Vue) {
-    Vue.prototype.getPhrasesForLocale = async (locale) => {
-        const phrasesModule = await import(`@/i18n/${locale}`)
-        return phrasesModule.default
-    }
+import de from '@/i18n/de'
+import en from '@/i18n/en'
 
-    const availableLocales = [ 'de', 'en' ]
+const Translation = {}
+Translation.install = function(Vue) {
+    const availableLocales = { de, en };
     const potentialLocale = navigator.language.substring(0, 2)
-    const activeLocale = availableLocales.includes(potentialLocale)
-        ? potentialLocale
-        : 'de'
-
-    const phrases = await Vue.prototype.getPhrasesForLocale(activeLocale);
+    const activeLocale = availableLocales.hasOwnProperty(potentialLocale) ? potentialLocale : 'de'
+    const phrases = availableLocales[activeLocale];
 
-    Vue.prototype.$activeLocale = activeLocale
     Vue.prototype.polyglot = new Polyglot({ phrases })
-    Vue.prototype.$t = function(text, context = {}) {
-        return this.polyglot.t(text, context)
-    }
+    Vue.prototype.$activeLocale = activeLocale
+    Vue.prototype.getPhrasesForLocale = (locale) => availableLocales[locale];
 
-    Vue.prototype.$locale = async function(newLocale) {
-        const phrases = await this.getPhrasesForLocale(newLocale)
+    Vue.prototype.$locale = function(newLocale) {
+        const phrases = this.getPhrasesForLocale(newLocale)
 
         this.$activeLocale = newLocale
         this.polyglot = new Polyglot({ phrases })
         this.$forceUpdate()
     }
+
+    Vue.prototype.$t = function(text, context = {}) {
+        return this.polyglot.t(text, context)
+    }
 };
 
 export default Translation