- Closes#1005.
- Adapt everything to use MACAddress type from containerization 0.20.0.
- Allocate MAC addresses for every container so that we have
deterministic IPv6 link local addresses.
- Add AAAA handling to ContainerDNSHandler.
- NOTE: Only works on Tahoe. On Sequoia, we don't have a good way to set
or determine the IPv6 network prefix when networks are created, so we
can't infer the IPv6 link local addresses for AAAA responses and we
instead return `NODATA`.