Only log and save in the cleanup when data objects were modiffied

[Jumping-Beaver]

When configuring a cleanup method in the DataHub importer, the cleanupElement function emits a log message for every stored object of the imported type that wasn't in the feed. For large amounts of data, this makes the logs harder to use, and these log messages are not very informative. It would be good to reduce the number of log messages.

Another improvement: The UnpublishStrategy currently saves every element it receives, but it should only save elements whose publication state it changes.

[github-actions]

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[sonarqubecloud]

Quality Gate passed

Issues
0 New issues
0 Accepted issues

Measures
0 Security Hotspots
0.0% Coverage on New Code
0.0% Duplication on New Code

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[Jumping-Beaver]

I have read the CLA Document and I hereby sign the CLA

[Jumping-Beaver]

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