Turn off SSH password and root login

sshd accepted passwords from the internet (about 12,000 failed logins a
day) and root logins with a key. Keys only now, no root, no X11 forwarding.

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>

roles/common/handlers/main.yml

@@ -0,0 +1,4 @@
+- name: reload ssh
+  ansible.builtin.systemd:
+    name: ssh
+    state: reloaded