Promote performance tuning to beta

[tnozicka]

Requirements

• [ ] Stable API
• [ ] Automatically detecting CRI endpoints from a Kubernetes API and/or exposing the option on operator config
• [ ] Consistently handle possible symlinks inside /mnt/hostfs like cri sockets, symlinks in other directories we inspect (possibly chroot)
• [ ] Split node-config-daemon into it's own binary (smaller size to copy)
• [ ] Verify informer handlers and logs in a steady state
• [ ] Support configuring sysctls on nodes #868
• [ ] Update docs to create labeled nodes by default

[mykaul]

Can be deferred to 1.9, I reckon.