Add support for custom traffic-group on self-ip

[Radiotic]

Is your feature request related to a problem? Please describe.

Not currently available via DO

When sending a Declarative Onboarding Request I get the error message that the only supported traffic-groups are traffic-group-1 and traffic-group-local-only:

        {
            "keyword": "enum",
            "dataPath": ".declaration.Common['DMZLAN_TG2_1'].trafficGroup",
            "schemaPath": "#/allOf/7/then/properties/trafficGroup/enum",
            "params": {
                "allowedValues": [
                    "traffic-group-local-only",
                    "traffic-group-1"
                ]
            },
            "message": "should be equal to one of the allowed values"
        },

This is problematic because we are running a active/active setup where both units are processing traffic. So we would need to be able to reference another traffic group than the 2 above with a pointer or similar.

Describe the solution you'd like

To be made available via DO

Describe alternatives you've considered

N/A

Additional context

What it looks like right now in tmsh:
net self WAFDCWAN_TG2 {
address x.x.x.x/x
floating enabled
traffic-group traffic-group-2
unit 2
vlan WAFDCWAN
}

[mdditt2000]

please open CSR "customer special request" with engineering