SUP 17176: Fix accessing files in the binary image cache to not create folders of old structure

[npomaroli]

Abstract

Accessing the binary image cache must not create directories of the old structure while searching cache files.
The migration of the old structure must delete the old directories even if they are empty or contain cache files which cannot be migrated because the binary no longer exists.

Checklist

General

• Added abstract that describes the change
• Added changelog entry to /CHANGELOG.adoc
• Ensured that the change is covered by tests
• Ensured that the change is documented in the docs

On API Changes

• Checked if the changes are breaking or not
• Added GraphQL API if applicable
• Added Elasticsearch mapping if applicable