Add support for specifying Network Devices

[kad]

With opencontainers/runtime-spec#1271 now merged in the runtime spec, we can start exploring how we can add support for adjusting this runtime spec field in the CDI spec.

[elezar]

Thanks @kad. Do we have an indidation as to when the merged commit will be released as an OCI Runtime Spec version bump?

[kad]

Approx 1-2 months timeframe. There are few other changes expected to runtime-spec before new release will be out

[aojea]

This is already implemented in 3 runtimes, runc just got added today opencontainers/runc#4538