Add the list of RCP users who should be allowed to make configuration changes...

The RCP team (+ Stuart) should be allowed to make deployment changes via Kayobe and Kolla-Ansible. The mechanism for this is always Ansible, so SSH public keys for the users mustbe appended to those service user authorized_keys files.

Here we use the "internal" SSH public-keys that are used for sysadmin traversal inside the DC networks.