Add nvim plugin and update vpn

modules/nix/school/default.nix

@@ -0,0 +1,19 @@
+{ lib
+, pkgs
+, config
+, ...
+}:
+
+with lib; let
+    cfg = config.simmer.school;
+    extraCerts = [ ./incommon-rsa-ca2.pem ];
+    citrix = pkgs.citrix_workspace_23_09_0.override { inherit extraCerts; };
+in
+{
+    config = mkIf cfg.enable {
+        environment.systemPackages = with pkgs; [
+            xournalpp
+            libreoffice
+        ] ++ optional cfg.citrix citrix;
+    };
+}