Disable public registriation to my gitea server

My gitea-server is basically my safe harbor for private git-projects. It
is not meant to be public.

Even more important that would shift responsibilities a lot, especially
legal liabilities may become important suddenly, when the server is
open.

Furthermore I can't guarantee a process availability when I cannot make
any assumptions about the usage. And, I cannot make such assumptions for
an open and public project which I maintain in my spare-time.

roles/k8s-setup/tasks/_gitea.yml

@@ -71,6 +71,8 @@
           email: "{{ gitea_admin_email }}"
         config:
           APP_NAME: "Gitea: Mein kleiner git-server"
+          service:
+            DISABLE_REGISTRATION: "true"
           markup.plantuml:
             ENABLED: "true"
             NEED_POSTPROCESS: "false"