[Enhancement] Add GitOps controller guidance to mutation section

[chipzoller]

Description

We need to add some guidance in the mutation docs for GitOps controllers, starting with Flux and Argo CD. Users should be aware how Kyverno will interact with both and what the necessary gotchas are as well as configuration recommendations.

Slack discussion

No response

[chipzoller]

Flux uses server-side apply and dry run to inspect the diff which allows Kyverno to fire and send back the object allowing Flux and Kyverno to essentially just "work". This puts slightly more load on Kyverno since each dry run requires Kyverno to mutate the resource, which is why sensible reconciliation time windows are recommended here.

See also: https://github.com/stefanprodan/gitops-kyverno#flux-vs-argo-drift-detection

[chipzoller]

argoproj/argo-cd#11574
argoproj/argo-cd#7285