Bundle javax.mail:mail for JDK support

[reftel]

Bundles javax.mail:mail, which is no longer included with the JVM.

Testing done

Ran a pipeline that uses the publishConfluence step on a Jenkins running on JVM 17 with release 163.vf906edb_73cce of confluence-publisher-plugin. The pipeline failed with a ClassNotFoundException due to not finding javax.mail.MessagingException. Made a local build of the same release, but with this patch applied. Re-ran the pipeline. This time, it worked.

Also ran com.sun.jersey.spi.service.ServiceFinder.find(javax.ws.rs.ext.MessageBodyReader.class, true).toClassArray() in the Script Console of the same Jenkins instance. With release 163.vf906edb_73cce, it failed with a ClassNotFoundException due to javax.mail.MessagingException not existing. With this change, no exception was thrown.

### Submitter checklist
- [x] Make sure you are opening from a **topic/feature/bugfix branch** (right side) and not your main branch!
- [x] Ensure that the pull request title represents the desired changelog entry
- [x] 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

[reftel]

@jhansche @jetersen Could either of you please review

[reftel]

Thanks for the review! How can we proceed to get this merged and released?

[lutin-malin]

LGTM (with manual substitution of the deps in the install folder, it fixes current version...)

[matthewpango]

Rebuilding plugin with javax.mail:mail works for me as well