🚨 Fix linter warnings of type 'name[casing]'

ansible-lint reads like this:

    name[casing]: All names should start with an uppercase letter.

While at it: Some task/handler names were slightly adapted to better
match what should be done.

roles/dd24_dyndns_cron/tasks/main.yml

@@ -13,6 +13,6 @@
     owner: root
     group: root
     mode: "0644"
-  notify: reload cron
+  notify: Reload cron
   # There is ansible.builtin.cron, but this makes configuration much
   # more complicated, so we stick to the template.