(1.32) Document control plane older release emulation

**This is a Feature Request**

**What would you like to be added**
Change pages such as https://kubernetes.io/releases/version-skew-policy/ to document that you can get Kubernetes to emulate running as an older release.

**Why is this needed**
v1.32 is likely to support emulating v1.31, so we had better lay the groundwork for this.
See https://github.com/kubernetes/enhancements/blob/master/keps/sig-architecture/4330-compatibility-versions/README.md

**Comments**
Really helpful: a diagram showing the supported skew and actual versions

/language en
/kind feature
/sig architecture