grafana-system: deploy grafana-operator

Adds the grafana-operator (grafana.integreatly.org CRDs + controller) so
Grafana and its dashboards/datasources can be managed declaratively as
CRs in a follow-up PR. Sits in the platform project like the other
operators (vm-system, cnpg-system).

Changes:
- Add grafana-system namespace + grafana-operator helm chart v5.24.0
  (watches all namespaces).
- Render CRDs inline (crds.immutable: false) so ArgoCD installs/manages
  the 13 grafana.integreatly.org CRDs instead of the skipped helm crds/
  subchart.
- Register apps/overlays/*/grafana-system in the platform ApplicationSet.

apps/base/grafana-system/kustomization.yaml

@@ -0,0 +1,6 @@
+---
+apiVersion: kustomize.config.k8s.io/v1beta1
+kind: Kustomization
+
+resources:
+  - namespace.yaml

apps/base/grafana-system/namespace.yaml

@@ -0,0 +1,7 @@
+---
+apiVersion: v1
+kind: Namespace
+metadata:
+  labels:
+    app.kubernetes.io/name: grafana-system
+  name: grafana-system

apps/overlays/au-syd1/grafana-system/kustomization.yaml

@@ -0,0 +1,16 @@
+---
+apiVersion: kustomize.config.k8s.io/v1beta1
+kind: Kustomization
+
+namespace: grafana-system
+
+resources:
+  - ../../../base/grafana-system
+
+helmCharts:
+  - name: grafana-operator
+    repo: https://artifactapi.k8s.syd1.au.unkin.net/api/v1/virtual/helm
+    version: "5.24.0"
+    releaseName: grafana-operator
+    namespace: grafana-system
+    valuesFile: values.yaml

apps/overlays/au-syd1/grafana-system/values.yaml

@@ -0,0 +1,16 @@
+# Watches all namespaces by default (namespaceScope: false) so it can manage the
+# Grafana instance + dashboards/datasources in the `grafana` namespace.
+#
+# Render the CRDs as normal templated manifests (instead of the helm `crds/`
+# subchart, which `helm template`/kustomize skip) so ArgoCD installs and manages
+# them alongside the operator.
+crds:
+  immutable: false
+replicas: 1
+resources:
+  requests:
+    cpu: 50m
+    memory: 128Mi
+  limits:
+    cpu: 500m
+    memory: 512Mi

argocd/applicationsets/platform.yaml

@@ -23,6 +23,7 @@ spec:
       - path: apps/overlays/*/elastic-system
       - path: apps/overlays/*/encapi
       - path: apps/overlays/*/externaldns
+      - path: apps/overlays/*/grafana-system
       - path: apps/overlays/*/inteldeviceplugins-system
       - path: apps/overlays/*/jfrog
       - path: apps/overlays/*/kanidm