Explore options for linking Gerrit and our public GitHub

The Qt Project from time to time gets external contributors that would much rather work with our public GitHub and upload pull requests than join our official Gerrit. We need to look into linking these two systems so that users can participate in GitHub and exchange comments with users in Gerrit seamlessly. Reasoning is that we also receive many complains about onboarding with Gerrit being too confusing/difficult/requiring client setup for just submitting a single, simple fix.

The idea is that if a user pushes a Pull Request to GitHub, the diff should be replicated to our Gerrit at codereview.qt-project.org and any actions on the pull request should be replicated to the gerrit-side such as new patchsets, comments on code, general comments to the PR, votes, and so on. When the PR is finally merged to the branch via the Gerrit change staging to CI by an Approver, the PR on GitHub should be closed automatically.

• Is there an existing integration from either side?
• What about CLAs? Contributors to Gerrit must sign a personal or corporate CLA before submitting code. Is this enforceable on GitHub?
• Current idea is that this should be a middleware service with API access to both sides, but would it be better to integrate to create our own integration for one of the systems to sync with the other?