Extend VPP to act as an edge device for IPv6 traffic where identifier / locator rewrite is required. Including (permissionless) extensions of the network.

Mechanisms include:

NPTv6 (inside site network to external site network 1:1 mapping)
NAT66 /64 (inside link (/64) to outside link)
NAT66 1:1 (inside host to outside host address)

This epic also covers the IPv6 mostly and IPv6 only use cases where either an IPv6 mostly host uses 464XLAT and a VPP NAT64 or an IPv6 only application uses a NAT64 to reach an IPv6 destination.