add links to other camp web apps

mkdocs.yml

@@ -47,7 +47,7 @@ nav:
   - timeline.md
   - tickets.md
   - travel.md
-  - parcel.md
+  - 'Parcel': parcel.md
   - facilities.md
   - hub.md
   - food.md
@@ -59,10 +59,16 @@ nav:
   - accessibility.md
   - styleguide.md
   - faq.md
+  - 'Principles of our event and community': 'https://help.ccc.de/principles.en.html'
+
+  - Quicklinks (External):
     - 'Map': 'https://map.events.ccc.de/camp/2023/map/'
-  - 'Matrix Chat': 'https://matrix.to/#/#camp2023:events.ccc.de'
+    - 'Hub (Wiki/Events/Assemblies/DMs…)': '/camp/2023/hub/'
+    - 'Fahrplan': 'https://events.ccc.de/camp/2023/hub/camp23/en/fahrplan'
+    - 'Chat (Matrix)': 'https://matrix.to/#/#camp2023:events.ccc.de'
     - 'Livestreams': 'https://streaming.media.ccc.de'
     - 'Recordings': 'https://media.ccc.de'
-  - 'Principles of our event and community': 'https://help.ccc.de/principles.en.html'
+    - 'Phonebook': 'https://guru3.eventphone.de/event.rb/phonebook'
+    - 'Engelsystem': 'https://engelsystem.events.ccc.de/'
   - 'Help!': 'https://help.ccc.de/index.en.html'
   - 'Legal Notice & Privacy Policy': 'https://legal.cccv.de'