Use openvpn-client@ and openvpn-server@ unit files on Ubuntu 18.04
Use openvpn-client@ and openvpn-server@ unit files on Ubuntu 18.04

The openvpn@ unit file is still present, but moving forward is better

Signed-off-by: Samuli Seppänen <be49b59234361de284476e9a2215fb6477f46673@openvpn.net>

Puppet-Finland/openvpn