feat: add authentification for collabora admin page via pam

https://sdk.collaboraonline.com/docs/installation/Configuration.html#admin-console

hosts/vm/collabora/collabora.nix

@@ -25,6 +25,13 @@
     };
   };
 
+  # Authentification pour la console d'administration (accès pour les nounous)
+  security.pam.services.coolwsd.text = ''
+    auth required pam_unix.so
+    auth required pam_wheel.so group=_nounou
+    account required pam_unix.so
+  '';
+
   services.nginx = {
     enable = true;