Inline jenkins-stapler-support

[basil]

A handful of annotation classes live in a separate jenkins-stapler-support library at https://github.com/jenkinsci/lib-jenkins-stapler-support, which hasn't been maintained in 6 years. I can't imagine anything other than Jenkins core consuming this library, and having it in a separate repository adds to the burden of maintaining it, so why not inline it into Jenkins core as we did with extras-executable-war a few years back. Its tests live in this repository anyway, so this unites the code with its tests, which is also a good thing. If this PR is accepted, I will archive the jenkins-stapler-support repository once it is no longer consumed by any LTS release.

Testing done

mvn clean verify -Dtest=jenkins.security.stapler.CustomRoutingDecisionProviderTest,jenkins.security.stapler.DoActionFilterTest,jenkins.security.stapler.DynamicTest,jenkins.security.stapler.GetterMethodFilterTest,jenkins.security.stapler.JenkinsSupportAnnotationsTest,jenkins.security.stapler.PreventRoutingTest,jenkins.security.stapler.Security400Test,jenkins.security.stapler.Security867Test,jenkins.security.stapler.Security914Test,jenkins.security.stapler.StaplerAbstractTest,jenkins.security.stapler.StaplerDispatchValidatorTest,jenkins.security.stapler.StaplerRoutableActionTest,jenkins.security.stapler.StaplerRoutableFieldTest,jenkins.security.stapler.StaplerRoutableGetterTest,jenkins.security.stapler.StaplerSignaturesTest,jenkins.security.stapler.StaticRoutingDecisionProvider2Test,jenkins.security.stapler.StaticRoutingDecisionProviderTest,jenkins.security.stapler.TypedFilterTest

Proposed changelog entries

N/A

Proposed upgrade guidelines

N/A

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5. New deprecations are annotated with @Deprecated(since = "TODO") or @Deprecated(forRemoval = true, since = "TODO"), if applicable.
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Desired reviewers

@mention

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2. Conversations in the pull request are over, or it is explicit that a reviewer is not blocking the change.
3. Changelog entries in the pull request title and/or Proposed changelog entries are accurate, human-readable, and in the imperative mood.
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[daniel-beck]

IIRC, motivation at the time was to make the annotations available to plugins with an older core dependency. This is no longer relevant for these annotations. If we need something similar again, we can always create a new library with new annotations.

[krisstern]

/label ready-for-merge

This PR is now ready for merge, after ~24 hours, we will merge it if there's no negative feedback.