[FR] webhook for enforced violations

[dustin-decker]

Add a configurable webhook to call when violations are enforced.

It should have a configurable endpoint, method, and body that can be templated via the go template format to support injection of violation parameters.

This would be useful for notifying when a policy has been enforced to a Slack channel, for example. In our experience enforced violations are rare when configured correctly, but we generally want to know about them when they happen.

[mark-adams]

👋 The k-rail project has been deprecated and is no longer under active development. We recommend taking a look at OPA Gatekeeper to see if it might meet your needs going forward.

Thanks for your contribution(s) to the project!