Parallelize unit tests

[ldeichmann]

Improve runtime of unit tests and integration tests to accelerate CI.

Checklist

The following aspects have been respected by the author of this pull request, confirmed by both pull request assignee and reviewer:

• Adherence to coding conventions
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• Adherence to javadoc conventions
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• Changelog update (necessity checked and entry added or not added respectively)
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• README update (necessity checked and entry added or not added respectively)
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• config update (necessity checked and entry added or not added respectively)
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• SDCcc executable ran against a test device (if necessary)
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