feat: Adding backend interfaces support to CNS

[shreyashastantram]

Reason for Change:

This feature adds backend interfaces support to CNS

Issue Fixed:

Requirements: CNS should be able to return back with PnPId to CNI with ipconfigs response. CNS should be able to determine the PnPID based on the macaddress.

• [ ] uses conventional commit messages
• [ *] includes documentation https://microsoft.sharepoint.com/:w:/t/Aznet/EQI_uDcvkwRDkjBX4X2yZo4BTkGR5g55ttvupXYG_TfC6Q?e=o8iR2s
• [ ] adds unit tests
• [ ] relevant PR labels added

Notes:

[github-actions[bot]]

This pull request is stale because it has been open for 2 weeks with no activity. Remove stale label or comment or this will be closed in 7 days

[nddq]

@shreyashastantram can you hit the Resolve conversation if the issue discussed in that conversation has been resolved, make the PR less clutter, thanks 🙂

[nddq]

/azp run Azure Container Networking PR

[azure-pipelines[bot]]

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