Improve ipset performance with large sets
Improve ipset performance with large sets

This commit updates kube-router to use `ipset restore` instead of calling `ipset add` multiple times in a row. This significantly improves its performance when working with large sets of rules.

Ref: https://github.com/cloudnativelabs/kube-router/issues/962

cloudnativelabs/kube-router,cloudnativelabs/kube-router