Runner cleanup - continuation

[juliobbv]

• Rename Agent/TestAgentCredential -> Runner/TestRunnerCredential
• Restore RunnerL0 tests
• Remove "job message" PII variable scrubbing code
• Rename multiple code instances of Agent to Runner

[TingluoHuang]

@juliobbv what's the status of the "v2" upload/download? is it enabled across all the rings and are we comfortable to delete v1 now? do we need to worries about if v2 broken and we need to temporary using v1?

[juliobbv]

@TingluoHuang we're in the process of turning v2 on across all scale units by end of this week. We haven't run into any issues, but if anything happens that requires us keeping the v1 code around for a bit longer, I'll cherry-pick that commit away from this PR and include it at a later time.

[bryanmacfarlane]

Users need to be able to still bind to V1 even after this code is removed - confirm that's still possible. I also agree with Ting that it's too soon to pull this out. Seems like we should keep it around for awhile in case we have to rollback. Also, how would we roll back?

[juliobbv]

@bryanmacfarlane FYI, with my artifact changes, the plugin version was kept at @v1 (i.e. it was not revved up), so workflows consuming the download/publish actions will automatically start calling the new Pipelines API endpoint (instead of Build2), once the FF is turned on. The Pipelines endpoint can read artifacts created from the Build2 endpoint.

That said, I'm going to cherry-pick the artifact build2 removal commit into its own PR, to not tie it to the lifetime of this set of changes. Turning the FF on in ring 0 and 1 has fortunately been uneventful so far, but I agree it's good to keep the old code for extra peace of mind.