Fixes gh-11987

Fixes gh-24522

* pr/24532:
  Avoid duplicates in MergedContextConfiguration

Closes gh-24532

Remove duplicate config attribute classes by using a `Set` rather
than a `List` in the `SpringBootTestContextBootstrapper`.

See gh-24532

Prior to this commit, running the bootBuildImage Gradle task on a
project configured for war packaging would result in a jar file being
built and used in the image instead of the war file. With this commit
an error will be thrown from the plugin in this case.

Fixes gh-24521

Closes gh-24486

Closes gh-24513

Closes gh-24472

Closes gh-24500

Fixes gh-24475

Closes gh-24494

This commit removes links to Jetty API and documentation as those links
are breaking every time the Jetty team releases a new version

See https://github.com/eclipse/jetty.project/issues/4546

Closes gh-24493

Closes gh-24463

Closes gh-24464

Closes gh-24465

Close gh-24462

Closes gh-24457

Closes gh-24456

Closes gh-24460

Closes gh-24459

See gh-24461

See gh-24458

See gh-24197

See gh-24197

See gh-24197

See gh-24197

See gh-24197

Update CI to generate images using an `oci-build-task` since
the `registry-image` resource cannot perform actual image builds.

See gh-24197

See gh-24197