Allow defining static mac adresses for SecondaryInterfaces

[meibensteiner]

Describe the problem/challenge you have
Im currently using the SecondaryInterface feature with the host interface. Every freshly created pod has a new MAC address which gets added to our network monitoring tool and the list is quite long already.

Describe the solution you'd like
Something similar to the tuning meta cni plugin where I can set a predefined mac address would be amazing.
https://www.cni.dev/plugins/current/meta/tuning/

Anything else you would like to add?
Just a lot of praise for the dev team. 🥇 💯