Name all tasks.
It would seems that the task creating the `fail2ban_ignore_ips` fact for
the whitelist exist in both main.yml and ip_whitelist.yml, one of them
might be superfluous.
Now the list of whitelisted ip addresses can be updated simply by
including the specific tasks in an external playbook without polluting
our role list.
This change takes effect for nginx, apache and fail2ban.