arrproxy: v0.6.0 self-migrating, drop external migrate Job

Bump arrproxy-api and arrproxy-ui to v0.6.0 and remove the psql migrate Job
plus its migrations ConfigMap. v0.6.0 applies its own schema at startup under
a Postgres advisory lock and holds /readyz until it is current, so the
external hook is dead weight and a drift trap.

apps/base/arrstack/arrproxy/kustomization.yaml

@@ -5,8 +5,6 @@ kind: Kustomization
 resources:
   - cnpg_cluster.yaml
   - cnpg_backup.yaml
-  - migrations-configmap.yaml
-  - migrate-job.yaml
   - vaultstaticsecret.yaml
   - tiers-configmap.yaml
   - oauth2-proxy-configmap.yaml