feat(messages): added frontend translation class

frontend/src/messages.js

@@ -0,0 +1,17 @@
+export class Translations {
+    static translations = {
+        'checkrangeTooltip' : {
+            'de' : 'Shift-Klick, um mehrere Zellen zu markieren.',
+            'en' : 'Shift-click to mark multiple cells.',
+        },
+    };
+
+    static getTranslation(key, language) {
+        let json = Translations.translations[key];
+        if(language === 'en') {
+            return json.en;
+        } else {
+            return json.de;
+        }
+    }
+};