Add very basic server based integration tests: * basic connect with 2 minutes stability check * ipv4/ipv6 * terminating openvpn service * mtu Using these tests from NM repo: * openvpn_ipv4 * openvpn_ipv6 * openvpn_set_mtu * openvpn_delete_active_connection * openvpn_persist NM repo: https://gitlab.freedesktop.org/NetworkManager/NetworkManager-ci/blob/master/nmcli/features/openvpn.feature