Generic Helm chart and production overlay split

The Hive Helm chart is now generic and no longer hardcodes Tuist-specific settings. Default values use a placeholder host, leave image pull secrets, External Secrets Operator integration, and Postgres S3 backup unconfigured, and support a secrets.existingSecret value for operators that bring their own Kubernetes Secret. Tuist’s production configuration has been moved into a separate values-production.yaml overlay, so the chart can be used by anyone deploying their own Hive instance.