[BUG-5656] Annotate Jobs with parent ScaledJob generation

[josefkarasek]

As reported in #5656, keda-operator Pod restart causes the deletion of existing Jobs (child resources of ScaledJob). The Jobs are re-created immediately, but the state/progress of the running Jobs is lost.

My approach to fixing this is to maintain relation between the ScaledJob and child Jobs using an Annotation: "scaledjob.keda.sh/generation": $(ScaledJob.Generation) This way the operator, during startup, will only delete Jobs with "scaledjob.keda.sh/generation" that doesn't match the generation of the parent ScaledJob.

Checklist

• [x] When introducing a new scaler, I agree with the scaling governance policy
• [x] I have verified that my change is according to the deprecations & breaking changes policy
• [x] Tests have been added
• [x] Changelog has been updated and is aligned with our changelog requirements
• [x] A PR is opened to update our Helm chart (repo) (if applicable, ie. when deployment manifests are modified)
• [x] A PR is opened to update the documentation on (repo) (if applicable)
• [x] Commits are signed with Developer Certificate of Origin (DCO - learn more)

Fixes #5656

[zroubalik]

/run-e2e internal Update: You can check the progress here