Introduce CRD for Iceberg table maintanance

提案されている CRD の形と、リンクされている Trino Iceberg のメンテナンスアクションのドキュメントから始めます。テーブルまたはスキーマのメンテナンスのスケジューリング、Trino への認証、保持設定の処理、Prometheus メトリクスの公開について、完了とは何を意味するのかを定義してください。この issue では Kubernetes CronJobs、アラート、Grafana ダッシュボードについても言及されています。

As a Trino Iceberg user I want to define a CR that allows me to regularly run maintenance actions on my tables.

• Come up with a CRD
• Figure out how to authenticate against Trino Cluster, e.g. always create a k8s Secret for a service user and add that into the authentication chain using Password file authentication as well as mount it into the k8s CronJob

Should

• Allow to run at whole schema, which iterates through tables
• Emit Prometheus metrics so we can alert on failures and have a Dashboard

Could

• Prometheus alters
• Grafana dashboard with e.g. files compacted, bytes and rows read/written

One possible solution would be to create a k8s CronJob for every maintenance CR.
CRD could look something like

spec:
  target:
    catalog: lakehouse
    schema: default
    table: my_table # Optional
  schedule:
    interval: 24h # using new Duration struct
    # OR
    cronExpression: XXX
  actions:
    - name: optimize
      fileSizeThreshold: 100MB # optional, otherwise let trino use it's internal default
    - name: expire_snapshots
      retentionThreshold: 7d # optional, otherwise let trino use it's internal default
    - name: remove_orphan_files
      # Document: The value for retention_threshold must be higher than or equal to iceberg.remove_orphan_files.min-retention in the catalog otherwise the procedure fails with a similar message: Retention specified (1.00d) is shorter than the minimum retention configured in the system (7.00d)
      retentionThreshold: 7d # optional, otherwise let trino use it's internal default