Use gson-api-plugin and update to Jenkins 2.414.3 and minor updates and improvements

[StefanSpieker]

Use gson-api-plugin as suggested by (#549)
and updated:

• Node to latest LTS (20.12.1)
• NPM to the bundled version (10.5.0)
• Jenkins to version 2.414.3 (because the bom has a version for gson-api and a recent matrix-auth version)
• Plugin to 4.80 (supersedes Update dependency org.jenkins-ci.plugins:plugin to v4.81 #507)
• ran npm audit fix

and minor improvements

• removed explicit version of matrix-auth, because 3.2.1 seems to be sufficient
• removed explicit test dependency of JUnit 4

Testing done

• Maven install locally passes.
• Started an interactive debugging session, but did not really connect to an Entra ID instance. Just checked the configure screen and the try connect button.

Submitter checklist

Beta Give feedback

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

[timja]

can you bump the baseline and bom to one of the versions on https://www.jenkins.io/doc/developer/plugin-development/choosing-jenkins-baseline/ please? that way the latest bom can be used too

[StefanSpieker]

bumped to 2.414.3 because 98% of the users, which use the latest version are on this or a newer version

[timja]

Thanks!