Improve marketing language switcher

public/lang/de/marketing.json

@@ -504,6 +504,10 @@
     "contact": "Kontakt",
     "discover_packages": "Packages entdecken",
     "language": "Sprache",
+    "language_de": "Deutsch",
+    "language_en": "English",
+    "language_changed": "{{language}} ausgewählt",
+    "language": "Sprache",
     "open_menu": "Menü öffnen",
     "close_menu": "Menü schließen",
     "cta_demo": "Jetzt ausprobieren",

public/lang/en/marketing.json

@@ -494,6 +494,10 @@
     "contact": "Contact",
     "discover_packages": "Discover Packages",
     "language": "Language",
+    "language_de": "Deutsch",
+    "language_en": "English",
+    "language_changed": "{{language}} selected",
+    "language": "Language",
     "open_menu": "Open menu",
     "close_menu": "Close menu",
     "cta_demo": "Try it now",