[Misc] Apply SonarCloud rule cpp:S3471

Description

• Removes Ceph RADOS Striper disk implementation (obsolete hangover from CASTOR days, not used in CTA)
• Declares all virtual functions in subclasses as override or final

Checklist

• Documentation reflects the changes made.
• Merge Request title is clear, concise, and suitable as a changelog entry. See our contributing docs

References

Closes #1372 (closed)