fix: ownerRef for driver pod, ensuring correct GC cascade

[Maleware]

Description

Solves: #701

Definition of Done Checklist

Author

• Changes are OpenShift compatible
• CRD changes approved
• CRD documentation for all fields, following the style guide.
• Helm chart can be installed and deployed operator works
• Integration tests passed (for non trivial changes)
• Changes need to be "offline" compatible
• Links to generated (nightly) docs added
• Release note snippet added

Reviewer

• Code contains useful comments
• Code contains useful logging statements
• (Integration-)Test cases added
• Documentation added or updated. Follows the style guide.
• Changelog updated
• Cargo.toml only contains references to git tags (not specific commits or branches)

Acceptance

• Feature Tracker has been updated
• Proper release label has been added
• Links to generated (nightly) docs added
• Release note snippet added
• Add type/deprecation label & add to the deprecation schedule
• Add type/experimental label & add to the experimental features tracker

[Maleware]

There is still an unsolved downside to it:

Pods which haven't had a CR and are still running while upgrading the operator won't be cleaned up and run into an error loop. I'm still unsure whether this can be solved in an reasonable amount of time and complexity. Thus I'd rather open another issue for this and discuss it separately.