L2TP CLI definition can be cleanup in the following ways:
- [x] combine IPv4 / IPv6 DNS servers, if its dns1 or 2 is irrelevant for the user, this should be mapped internally (see SSTP DNS configuration)
- [ ] Reuse RADIUS XML -> T2110
- [x] convert WINS server to multi node
- [ ] check if accel can be supervised by systemd