Mirate to using the GitHub Checks API

[bensze01]

Summary:

Migrate from using the Commit Status API and the GitHub Notfiy step to the GitHub Checks API and the corresponding Jenkins plugin.

Motivation:

This would allow us to display rich status reports on GitHub, similar to the Travis integration, enabling:

• Reporting more possible result types
  • Commit Status API: error, failure, pending, or success
  • Checks API:: action_required, cancelled, failure, neutral, success, skipped, stale, timed_out
• Displaying build log snippets or longer failure reports on GitHub
  • Commit Status API: Short context + 140 character description
• Display custom buttons on GitHub, clickable by users with write access to the repo, which send a webhook to Jenkins
  • This would allow us to construct a native one-click UI for adding the commit hash of the PR-head to the CI's auto-buid allowlist
    • Useful for PRs from untrusted contributors and PR-merge jobs in particular, which be triggered multiple times for the same hash

Prerequisites:

• Install the Github Checks plugin on the CIs:
  • Internal CI
  • OpenCI
• Set up a (pair of) (Organization) GitHub app(s) for our Jenkins instances
  • See this detailed guide