feat: migrate to artifactapi 3+ (#197)

What changed:
- Adds new v3 API and UI deployments (separate api-deployment.yaml, ui-deployment.yaml) alongside the existing monolithic artifactapi-deployment.yaml
- Adds CNPG PostgreSQL cluster + pooler to replace the standalone postgres deployment
- Adds new api-env configmap, new Vault secrets (postgres-credentials, environment), and a second VaultAuth (default1)
- Adds new services targeting the split api and ui selectors
- Adds HPAs for both new deployments
- Updates kustomization to include all new resources

---------

Co-authored-by: Ben Vincent <ben@unkin.net>
Reviewed-on: #197

apps/base/artifactapi/ui-hpa.yaml

@@ -0,0 +1,41 @@
+---
+apiVersion: autoscaling/v2
+kind: HorizontalPodAutoscaler
+metadata:
+  name: ui-hpa
+  namespace: artifactapi
+spec:
+  scaleTargetRef:
+    apiVersion: apps/v1
+    kind: Deployment
+    name: ui
+  minReplicas: 2
+  maxReplicas: 10
+  metrics:
+    - type: Resource
+      resource:
+        name: cpu
+        target:
+          type: Utilization
+          averageUtilization: 60
+  behavior:
+    scaleUp:
+      stabilizationWindowSeconds: 0
+      selectPolicy: Max
+      policies:
+        - type: Percent
+          value: 100
+          periodSeconds: 30
+        - type: Pods
+          value: 4
+          periodSeconds: 30
+    scaleDown:
+      stabilizationWindowSeconds: 300
+      selectPolicy: Min
+      policies:
+        - type: Percent
+          value: 10
+          periodSeconds: 60
+        - type: Pods
+          value: 2
+          periodSeconds: 60