[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

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

Fixes #5656

[zroubalik]

Looking good, thanks! Could you please also update changelog?

[zroubalik]

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

[zroubalik]

@josefkarasek the static check si failing on the Changelog entry, it needs to be alphabetically sorted, also please move this into Improvements section - it is an user-facing issue.

The rest looks good, thanks