The *cert* role is intended to be a generic, reusable role to copy an
X.509 certificate and/or private key file to managed nodes. It is
intended to be included in a playbook with at least the `cert_src` and
`cert_dest` variables defined, e.g.:
```
- hosts: whatever
roles:
- role: cert
cert_src: whatever.cer
cert_dest: /path/to/whatever.cer
```