[Spike] Investigate replacing bundled Redis with official Valkey chart

Summary

GitLab chart currently bundles (bitnami) Redis chart. Because of licence changes to Redis and to Bitnamis build policies we are currently unable to upgrade the Chart and the images.

Currently usage of (Bitnami) Redis in GitLab chart:

• Non-production ready component, only simple deployments supported for PoC/test environments.
• No sentinels or redis cluster deployments are supported.
• Production deployments should use a external Redis: https://docs.gitlab.com/charts/advanced/external-redis/.
• Persistence is enabled by default

Acceptance Criteria

• Investigate replacing Redis with Valkey in GitLab chart
• Investigate need of (persistent) data migration
• Gaps between (bitnami) Redis and Valkey charts identified