Deploy new website under hamburg.ccc.de

Make next.hamburg.ccc.de hamburg.ccc.de and add redirects to handle URLs
of the old website deployment properly.
Also redirect the old spaceapi endpoint to the new one.

Add staging.hamburg.ccc.de for hosting upcoming changes (PRs).
Also give it a robots.txt, since its contents don't need to show up in
search engines.

Add www.hamburg.ccc.de and let it redirect to hamburg.ccc.de.

config/hosts/public-web-static/virtualHosts/default.nix

@@ -5,7 +5,9 @@
     ./branding-resources.hamburg.ccc.de.nix
     ./c3cat.de.nix
     ./element.hamburg.ccc.de.nix
-    ./next.hamburg.ccc.de.nix
+    ./hamburg.ccc.de.nix
     ./spaceapi.hamburg.ccc.de.nix
+    ./staging.hamburg.ccc.de.nix
+    ./www.hamburg.ccc.de.nix
   ];
 }