[otap-df-quiver] Add better handling for orphaned segment files

[AaronRM]

Follow up item from this PR conversation. The segment cleanup being added in #1764 needs to add handling for the edge case where segment files are orphaned after not being deleted successfully.

Quiver should:

1. Track these orphaned files when deletes fail
2. Occasionally re-attempt cleanup
3. Log the issue in case operators need to manually intervene
4. Also scan for and detect orphaned files at startup