[Configurable Logging] Prepare release and verify upgrade procedure

[a-thaler]

Description When https://github.com/kyma-project/kyma/issues/11236 is ready to be released, several things need to be done in order to get the new component installed by default and the old functionality disabled

Criterias

• [x] The new component is enabled by default by all means of installation (CLI, pure reconciler, SAP offering) (PR #15057)
• [x] Feature toggle is disabled by default -> New fluent-bit is pushing logs to loki as loki-logPipeline is active
• [ ] Old fluent-bit is not pushing logs to loki anymore (disable output plugin by re-using the disabled feature flag)
• [x] Docu is not describing anymore how to enable the feature (PR #15070)
• [x] Docu is not using "alpha" anymore. The CRD stays alpha for now but the feature itself is regular
• [ ] Assure that an upgrade from standard kyma 2.5 cluster works as expected
  • [x] Open Source
  • [ ] SKR
• [ ] Have release notes ready
• [ ] Ensure to have a cleanup script to delete the logging fluent-bit DaemonSet (PR #15092)

[kyma-stale-bot[bot]]

This issue has been automatically marked as stale due to the lack of recent activity. It will soon be closed if no further activity occurs. Thank you for your contributions.

[kyma-stale-bot[bot]]

This issue has been automatically marked as stale due to the lack of recent activity. It will soon be closed if no further activity occurs. Thank you for your contributions.

[skhalash]

The following acceptance criterium will not be done:

• Old fluent-bit is not pushing logs to Loki anymore (disable output plugin by re-using the disabled feature flag)

In order to achieve this, we would have to replace the old fluent-bit output with null and then, in a subsequent version, disable the subchart rendering. This 2-step process seems to be too much. Anyway, the old fluent bit will push logs during a short time window after the upgrade until the cleanup script is executed, which is an acceptable tradeoff.