Adds the valkey-operator (v0.5.0) as a platform app so a later change can
replace the self-managed redis Deployment with a Valkey CR.
- Add apps/base/valkey-operator-system (namespace)
- Add apps/overlays/au-syd1/valkey-operator-system pulling the valkey-operator
0.5.0 chart from the artifactapi virtual helm repo, with includeCRDs and the
operator image routed through the artifactapi ghcr proxy
- Register the app path in the platform ApplicationSet