Fix technical debts

[siegfriedweber]

Description

The remaining TODOs are fixed or removed if not necessary anymore.

Part of #2

Definition of Done Checklist

Author

• Changes are OpenShift compatible
• Helm chart can be installed and deployed operator works
• Integration tests passed (for non trivial changes)
• Changes need to be "offline" compatible

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

[adwk67]

Just one question (that does not need to block the PR). LGTM.

[adwk67]

changelog?

[siegfriedweber]

changelog?

I am not sure if a changelog entry is required here. The only user-facing change is that environment variable names in envOverrides are now validated. Other than that, only the code quality was improved.