feat: add jdk download scripts from jenkinsci/docker

[lemeurherve]

This PR adds the jdk download scripts introduced in jenkinsci/docker#1847 for the controller image, reused in jenkinsci/docker-agent#786 for the agent and inbound agent images, and in jenkinsci/docker-ssh-agent#404 for the SSH agent image.

Having a common source for these scripts will allow adding updatecli manifests in these repositories to track their changes from a single source of trust while controlling their lifecycle independently.

Discussing the location of these scripts with @dduportal, I first proposed the shared pipeline library as it's already configured on every project built on *.ci.jenkins.io. But as they're used only by Docker when building container images it made more sense to put them here.

It would also allow introducing tests for these scripts that could be run from the pipeline of this repo without needing them in all consumer repositories.

[dduportal]

Discussing the location of these scripts with @dduportal, I first proposed the shared pipeline library as it's already configured on every project built on *.ci.jenkins.io. But as they're used only by Docker when building container images it made more sense to put them here.

To be precise, the proposal I made to host it in the repository here is that the Jenkins infra also have the same needs but not only on Docker images:

• The script to print the JDK URL could be used instead of specific logic:
  • On Puppet for ci.jio, trusted.ci and cert.ci when rendering templates for Jenkins JDK tools config in JCasc: https://github.com/jenkins-infra/jenkins-infra/blob/production/dist/profile/templates/jdk-adoptium-url.erb
  • On Kubernetes for infra.ci when updatecli uses a shell script to populate the inline JCasc setup for Jenkins JDK tools

I believe we might have other usages (jenkins-infra/packer-images ? etc.) not defined yet, hence the proposal to move it here instead of pipeline librarie repository or jenkinsci GH org.

[dduportal]

LGTM!

Nitpick: as per my comment, the scope is wider then only docker so I would suggest to use a directory named temurin or adoptium. But not a blocker at all!