GitHub Actions next steps

[barchetta]

Issue #4828 (PR #4830) covers doing an initial implementation of a PR validator using GitHub actions.

This issue covers next steps:

• Parallelization
  • [x] Basic: examples, TCK #5011
  • [x] More advanced sharding
• Testing
  • [x] Try test containers #5026
  • [x] #5021
  • [x] Process junit test results (https://github.com/marketplace/actions/junit-report-action)
  • [ ] #6717
  • [x] Native image (once we have a released version for Java 19) matrix
• Jobs
  • [ ] Setup an internal runner
  • [ ] Release job on internal runner
  • [x] On schedule (nightly) jobs
• Other
  • [x] Add OGHO OCA checker
  • [x] Investigate using workflow_run to create a single workflow that can be specified in the repository PR validation configuration (instead of specifying all of the checks individually).
  • [ ] Evaluate if we need to re-validate PRs on every new commit to branch
  • [ ] Slack integration
  • [x] Evaluate if we want Fail Fast: with shorter job times and ability to retry individual jobs, maybe we don't want this?
  • [x] Archive arbitrary files
• Migrate PR validation
  • [x] main #4830
  • [x] helidon-3.x #6481
  • [x] helidon-2.x #6516
  • [x] helidon-1.x #6517

[romain-grecourt]

See #9111