Is your feature request related to a problem? Please describe.

Current IPv6 support is coupled with calico which is not choice by default on the k0s clusters.

During the times initial Ipv6 support was implemented we didn't use kube-router as default CNI and during the switching of the default CNI, kube-router wasnt' yet ready for ipv6

With the upcoming 2.X release, kube-router is going to have enhanced IPv6 support and this is a good point in time to rework our codebase as well.

We should allow using IPv6 with kube-router (once 2.X released).

More over, current implementation supports only dual-stack mode and at least investigation for support of IPv6-only clusters should be done.

Related links:

https://github.com/cloudnativelabs/kube-router/blob/master/docs/ipv6.md

#1292

#1726