Fix a problem with a platform-specific path conversion.

[oheger-bosch]

Issue: eclipse#591.

CSVArtifactMapper tries to convert paths to source files to relative
paths, so that they are not specific to a local configuration.
However, for absolute paths that are not below the base directory,
this obviously does not work reliably on all platforms - and does not
make any sense either. So such paths are now stored as absolute paths.

Please provide a summary of your changes here.

• Which issue is this pull request belonging to? (Refer to issue here)
• How is it solving the issue?
• Did you add or update any new dependencies that are required for your change?

Request Reviewer

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@blaumeiser-at-bosch @neubs-bsi

Type of Change

Mention one of the following:
bug fix | new feature | improvements | documentation update | CI | Other

Type of change:
improvements

How Has This Been Tested?

If you have added any changes that require additional tests, or changes in tests, you should implement them and describe them here.
All test that passed before your contribution should pass after it as well.
A new test case has been added to check the concrete problem.

Checklist

Must:

• All related issues are referenced in commit messages

Optional: (delete if not applicable)

• I have provided tests for the changes (if there are changes that need additional tests)
• I have updated the documentation accordingly to my changes

[sonarqubecloud]

Kudos, SonarCloud Quality Gate passed!

0 Bugs
0 Vulnerabilities (and 0 Security Hotspots to review)
3 Code Smells

100.0% Coverage
0.0% Duplication

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[blaumeiser-at-bosch]

It even builds on my machine