Add a init bucket job

General MR

Adds a bucket-init Job to the MinIO package to reliably create buckets declared in upstream.tenant.buckets, and adds ttlSecondsAfterFinished to prevent Helm upgrade failures caused by the static Job name.

Packages that deploys the Grafana rollout-operator as a sub-chart (like Mimir and Loki), which installs admission webhooks (no-downscale, prepare-downscale, pod-eviction) that intercepts and blocks StatefulSet UPDATE operations within the shared release namespace, will encounter failures with MinIO Tenant updating the MinIO Tenant statefulsets.

The bucket-init Job in this MR mitigates the initial bucket creation problem, though future/further updates to the MinIO tenant will be blocked by the rollout-operator's admission webhooks. Until a fix is in the upstream, the mitigation choice is either 1) deploy the MinIO in a separate namespace from Mimir or 2) disable the Grafana rollout-operator

Changes

• Added chart/templates/bigbang/bucket-init-job.yaml — a post-install Job that directly calls the MinIO S3 API to create buckets declared in upstream.tenant.buckets
• Added ttlSecondsAfterFinished: 300 to the Job spec so completed Jobs are automatically garbage collected after 5 minutes, preventing helm upgrade conflicts on immutable Job resources
• Added registry1.dso.mil/ironbank/big-bang/base:2.1.0 image reference to Chart.yaml for use by the Job container

Relevant logs/screenshots

N/A

Linked Issue

Relates to #196 (closed)

Upgrade Notices

N/A