Add rapid_diffs feature flag for Rapid Diffs effort
We should contain all the development of Rapid Diffs behind a rapid_diffs
feature flag. groupcode review should be maintaining it during it's lifecycle: creation, support, rollout, deletion.
We should contain all the development of Rapid Diffs behind a rapid_diffs
feature flag. groupcode review should be maintaining it during it's lifecycle: creation, support, rollout, deletion.