Add dns role
Add a role* to provision
playbook that changes the default nameservers from the provider and set the Cloudfare ones instead.
The reason for this change is that, sometimes, DNS queries fail to resolve, triggering false-positive alerts.
Also, it fixes some complaints from the Ansible linter.
** Actually, a collection. That is because we're currently unable to push standalone roles to Ansible Galaxy from Gitlab CI.
Edited by Daniel Palomar