[EVPN MH][CLI config] add support for EVPN MH feature

[dpolishchukgl]

What I did

Added a command to change the mac address for portchannel interfaces

How I did it

• added config portchannel mac-addr set command

How to verify it

root@sonic:/# config portchannel add PortChannel11
root@sonic:/# ip a s PortChannel11
50: PortChannel11: <NO-CARRIER,BROADCAST,MULTICAST,UP> mtu 9100 qdisc noqueue state DOWN group default qlen 1000
    link/ether 22:ef:3a:cc:22:bf brd ff:ff:ff:ff:ff:ff
root@sonic:/# config portchannel mac-addr set PortChannel11 00:11:22:33:44:55
root@sonic:/# ip a s PortChannel11
50: PortChannel11: <NO-CARRIER,BROADCAST,MULTICAST,UP> mtu 9100 qdisc noqueue state DOWN group default qlen 1000
    link/ether 00:11:22:33:44:55 brd ff:ff:ff:ff:ff:ff

Previous command output (if the output of a command-line utility has changed)

New command output (if the output of a command-line utility has changed)