Implement VRF

[frederic-loui]

Implement VRF feature.

This will remove any ambiguity and make all object VRF aware.
At the present time rtnetlink is not completely ready, but this is WIP here

[rwestphal]

For VRF support, we'll need to check out RFC 8529 to understand how VRFs should be handled from a management perspective. Also, yang2-rs will need to be extended to expose libyang's YANG schema mount functionality.

Aside from that, the protocol implementations should require little to no changes in order to support VRFs. All protocols already support multiple instances, which are well isolated one from another. We'll just need the ability to bind protocol instances to VRFs as specified in the configuration.

At the present time rtnetlink is not completely ready, but this is WIP here

Thanks for the heads-up. I see that the PR was merged already. It's good to know rtnetlink won't need further changes when it comes to adding VRF support in Holo.