There's currently no validation of the Istio and IstioRevision CRs apart from what's in the CRD schema and in the reconciliation code. We need to validate a few additional things such as:

• does the IstioRevision.spec.values.revision match the IstioRevision.metadata.name
• does the IstioRevision.spec.values.global.istioNamespace match IstioRevision.spec.namespace
• etc.

Instead of using a validation webhook, we should use CEL validation.