move helmify readme to website

[sozercan]

Describe the solution you'd like today, helmify readme (https://github.com/open-policy-agent/gatekeeper/tree/master/cmd/build/helmify/static) is static and not versioned. When we add or change values, it is not clear what the values correspond with what GK releases.

we should move this to website and version it so it's clear that a specific version of GK has specific values

Anything else you would like to add: [Miscellaneous information that will assist in solving the issue.]

Environment:

• Gatekeeper version:
• Kubernetes version: (use kubectl version):