[JENKINS-73344] Adapt GitLab for Jetty 12 (EE 9)

[basil]

See JENKINS-73344.

[krisstern]

LGTM

[basil]

Thanks @krisstern! Can this please be released?

[krisstern]

Sure @basil! Let me make a release now

[basil]

Thank you very much!

[daniel-beck]

This change broke mvn hpi:run:

[WARNING] Failed startup of context o.e.j.m.p.MavenWebAppContext@3e752d61{Jenkins v2.475,/jenkins,file:///Users/danielbeck/Repositories/github.com/jenkinsci/gitlab-plugin/target/jetty/webapp/,UNAVAILABLE}{/Users/danielbeck/.m2/repository/org/jenkins-ci/main/jenkins-war/2.475/jenkins-war-2.475.war}
java.lang.NoClassDefFoundError: jakarta/servlet/ServletContextListener
    at java.lang.ClassLoader.defineClass1 (Native Method)
    at java.lang.ClassLoader.defineClass (ClassLoader.java:1017)
    at java.security.SecureClassLoader.defineClass (SecureClassLoader.java:150)
    at java.net.URLClassLoader.defineClass (URLClassLoader.java:524)
    at java.net.URLClassLoader$1.run (URLClassLoader.java:427)
    at java.net.URLClassLoader$1.run (URLClassLoader.java:421)
    at java.security.AccessController.doPrivileged (AccessController.java:712)
    at java.net.URLClassLoader.findClass (URLClassLoader.java:420)
    at org.eclipse.jetty.webapp.WebAppClassLoader.foundClass (WebAppClassLoader.java:594)
    at org.eclipse.jetty.webapp.WebAppClassLoader.loadAsResource (WebAppClassLoader.java:567)
    at org.eclipse.jetty.webapp.WebAppClassLoader.loadClass (WebAppClassLoader.java:502)
    at java.lang.ClassLoader.loadClass (ClassLoader.java:525)

[krisstern]

@basil Could you please take a look?

[basil]

You'll need to run Maven with -Dhpi-plugin.version=3.58 until jenkinsci/plugin-pom#1004 is released and adopted.

[basil]

Fixed in #1702