RH124 Ch 12: Configure IPv4 and IPv6 with nmcli

Name: WebAsha Technologies
Address: Pune, Maharashtra, IN

servera is getting an extra service address and joining the IPv6 test network. Update the `eth1` connection profile with nmcli so the changes are live now and survive reboots. Do not touch `eth0`, and keep the existing `172.25.250.10/24` address.

Tasks

Add the IPv4 address 172.25.250.20/24 to connection eth1, keeping 172.25.250.10/24.
Set the IPv4 gateway of eth1 to 172.25.250.254 and its DNS server to 172.25.250.254.
Give eth1 the static IPv6 address fd00:250::10/64.
Make sure the eth1 connection comes up automatically at boot.