Changed DHCP table name to DHCP_RELAY

[kellyyeh]

Why I did it

DHCP is rather generic and can be used for DHCP servers/other options in future.

How I did it

Changed corresponding name in minigraph to Dhcprelay and changed "DHCP" table name to "DHCP_RELAY" in config.

'DHCP_RELAY': {
'Vlan1000': {
'dhcpv6_servers': [
'fc02:2000::1',
'fc02:2000::2'
],
'dhcpv6_option|rfc6939_support': 'true'
},
'Vlan2000': {
'dhcpv6_servers': [
'fc02:2000::3',
'fc02:2000::4'
],
'dhcpv6_option|rfc6939_support': 'false'
}
}

How to verify it

Which release branch to backport (provide reason below if selected)

• 201811
• 201911
• 202006
• 202012
• 202106

Description for the changelog

A picture of a cute animal (not mandatory but encouraged)

[tahmed-dev]

the Dhcpv6OptionRfc6939 is not in the minigraph, however it will be in the config and is always on.

[tahmed-dev]

Sorry, I missed that earlier. There will no new node in the minigraph with DhcpRelay name. The server/helper IPs will be provided as follows:

<VlanInterfaces>
<VlanInterface>
<ElementType>VlanInterface</ElementType>
<Name>Vlan2</Name>
<AttachTo>Ethernet2/1;Ethernet2/3;Ethernet4/1;Ethernet4/3;Ethernet6/1;Ethernet6/3;Ethernet12/1;Ethernet12/3;Ethernet14/1;Ethernet14/3;Ethernet16/1;Ethernet16/3;Ethernet18/1;Ethernet18/3;Ethernet20/1;Ethernet20/3;Ethernet22/1;Ethernet22/3;Ethernet28/1;Ethernet28/3;Ethernet30/1;Ethernet30/3;Ethernet32/1;Ethernet32/3;Ethernet1/1;Ethernet3/1;Ethernet5/1;Ethernet11/1;Ethernet13/1;Ethernet15/1;Ethernet17/1;Ethernet19/1;Ethernet21/1;Ethernet27/1;Ethernet29/1;Ethernet31/1</AttachTo>
<FhrpProtoType i:nil="true"/>
<Type i:nil="true"/>
<DhcpRelays>13.107.194.100;13.107.194.101;13.107.194.102;13.107.194.103;10.254.32.207;10.254.32.223;10.254.32.95;10.254.32.127;10.254.32.191;10.254.32.159;10.254.45.31;10.254.45.63</DhcpRelays>
<Dhcpv6Relays>2603:10e1:0:1::;2603:10e1:0:1::1;2603:10e1:0:1::2;2603:10e1:0:1::3</Dhcpv6Relays>
<VlanID>2</VlanID>
<Tag>2</Tag>
<Subnets>25.99.157.0/26</Subnets>
<MacAddress i:nil="true"/>
<SecondarySubnets/>
</VlanInterface>
</VlanInterfaces>

[qiluo-msft]

This PR could not be cleanly cherry-pick to 202012. Please submit another PR.