chore: added hint to default hetzner ssh keys

- always add them to hetzner clound console.
  server creation will be broken if not

group_vars/all/plain.yml

@@ -78,7 +78,9 @@ gitlab_ansible_user_name: "gitlabci"
 
 backupuser_user_name: backupuser
 
-# used for root-access by hetzner on server creation (@see cloud console/security/ssh-keys)
+# used for root-access by hetzner on server creation
+# all ssh keys have to be available to hetzner cloud
+# (@see cloud console / security / ssh-keys) (web ui)
 default_hetzner_ssh_keys:
   - "claus.paetow@netgo.de"
   - "friedrich.goerz@netgo.de"