Draft: Demonstrate bundling different Java distributions

What does this MR do?

This merge request demonstrates bundling different Java distributions in custom images. We bundle different versions of Java using asdf via asdf-java. I've bundled correto-8 and javafx-8 as advised in this Zendesk ticket (internal link).

What are the relevant issue numbers?

https://gitlab.com/gitlab-com/sec-sub-department/section-sec-request-for-help/-/issues/145+

Notes

1. This merge request should not be merged.
2. There is no javafx-8 for aarch64 with asdf-java.
3. New tests were added for the new Java distributions to spec/gemnasium-maven_image_spec.rb.
4. Many existing tests were removed from spec/gemnasium-maven_image_spec.rb because they were causing the job to time out.

Does this MR meet the acceptance criteria?

• Changelog entry added
• Documentation created/updated for GitLab EE, if necessary
• Documentation created/updated for this project, if necessary
• Documentation reviewed by technical writer or follow-up review issue created
• Tests added for this feature/bug
• Job definition updated, if necessary
  • Auto-DevOps template
  • Job definition example
  • CI Templates
• Conforms to the code review guidelines
• Conforms to the Go guidelines
• Security reports checked/validated by reviewer