Make permissions matrix-auth-3.0+ compatible

[eva-mueller-coremedia]

Make permissions matrix-auth-3.0+ compatible by adding support to explicitly assign permissions to groups or users.

With https://github.com/jenkinsci/matrix-auth-plugin/releases/tag/matrix-auth-3.0 ambiguous permissions will show a warning. With this change, matrix-auth-3.0+ users can resolve the warning by using the appropriate methods.

Closes #1249

See also https://issues.jenkins.io/browse/JENKINS-67411

Testing done

Added test cases and manually deployed and tested the hpi on a Jenkins 2.440.3 instance.

Job DLS

UI

XML

Submitter checklist

• Make sure you are opening from a topic/feature/bugfix branch (right side) and not your main branch!
• Ensure that the pull request title represents the desired changelog entry
• Please describe what you did
• Link to relevant issues in GitHub or Jira
• Link to relevant pull requests, esp. upstream and downstream changes
• Ensure you have provided tests - that demonstrates feature works or fixes the issue

[eva-mueller-coremedia]

@basil @jamietanna - are you still the main maintainers? It would be great if you could have a look at this PR.

[jamietanna]

As per https://github.com/jenkinsci/job-dsl-plugin?tab=readme-ov-file#jenkins-job-dsl-plugin I'm looking for support with maintainence.

I appreciate that this is fixing a warning, but I think my priority - if I were to be able to have time to support the plugin - would be to triaging the other outstanding issues and work out priority from there

[eva-mueller-coremedia]

As per jenkinsci/job-dsl-plugin#jenkins-job-dsl-plugin I'm looking for support with maintainence.

I appreciate that this is fixing a warning, but I think my priority - if I were to be able to have time to support the plugin - would be to triaging the other outstanding issues and work out priority from there

Sure, prioritize as best for you. Glad to see that there is a maintainer left.

I would like to emphasize that this also addresses https://issues.jenkins.io/browse/JENKINS-67411 - maybe a coin to raise this issue in its priotity.

[basil]

Thanks for the PR!