Mark taints stable

[marquiz]

What would you like to be added:

Remove the experimental statements related to taints. Both in the docs and in the code.

Why is this needed:

Node tainting has been around since NFD v0.12. No bugs/issues have been reported (at least in a long while).

[marquiz]

/milestone v0.17

[k8s-triage-robot]

The Kubernetes project currently lacks enough contributors to adequately respond to all issues.

This bot triages un-triaged issues according to the following rules:

• After 90d of inactivity, lifecycle/stale is applied
• After 30d of inactivity since lifecycle/stale was applied, lifecycle/rotten is applied
• After 30d of inactivity since lifecycle/rotten was applied, the issue is closed

You can:

• Mark this issue as fresh with /remove-lifecycle stale
• Close this issue with /close
• Offer to help out with Issue Triage

Please send feedback to sig-contributor-experience at kubernetes/community.

/lifecycle stale