Remove JDK17 from controller images

[lemeurherve]

As Jenkins Core 2.545 now requires JDK21, JDK17 images must be removed from Weekly releases, and from LTS releases after the next major LTS, but not from incoming LTS 2.541.x releases.

Refs:

• Removal of JDK17 (aka "Require Java 21 or newer") in Jenkins Core mailing list thread
• https://www.jenkins.io/changelog/2.545
• Require Java 21 or newer jenkins#26018
• Weekly 2.545 images have been published with JDK17 tags by mistake #2182
• LTS 2.541.1 release checklist jenkins-infra/release#811

[Pnkcaht]

I can take this one 👍
Plan is to handle this in a release-line–aware way rather than a blanket removal:

• Ensure JDK17 is excluded from Weekly controller images

• Keep JDK17 available for LTS 2.541.x

• Prevent JDK17 from being built/published for the next LTS line and beyond

I’ll align the controller image build matrix and tagging logic with the Jenkins core Java requirements, reusing the release-line differentiation introduced recently, and make sure we have guardrails to avoid publishing JDK17 images where they’re no longer supported.

I’ll post updates once I have a fork and a draft PR.

[lemeurherve]

JDK17 removed from Weekly images in #2179, for confirmation on next Tuesday.