The goal is to always find an interface with an address, preferring
sandbox interfaces, but falling back to the first address found.
A test was added against a known CNI plugin output that was not handled
correctly before.
When we iterate over the interfaces returned from CNI setup, we filter for one
with the `Sandbox` field set. Ensure that if none of the interfaces has that
field set that we still return an available interface.
CNI network configuration is currently only supported on Linux.
For now, add the linux build tag so that the deadcode linter does
not trip over unused CNI stuff on macOS.
* ar: support opting into binding host ports to default network IP
* fix config plumbing
* plumb node address into network resource
* struct: only handle network resource upgrade path once
