Add Kindnet as a networking provider (spec + validation)

Add Kindnet as a networking provider (spec + validation): a task in MiMo-V2.6-RL-harbor-code: MiMo-V2.6-RL Code (Harbor) (Harbor dataset). kops should understand kindnet (https://github.com/aojea/kindnet) as a CNI/networking provider that users can configure on a cluster. For this change we only…