Implement feature flags for KAS

Problem to solve

KAS now has enough users that we can benefit from incremental rollout of changes with quicker rollback than what our production deployment pipeline can offer. For example, !609 (merged) would have been a good candidate for a feature flagged change.

Proposal

We've added an implementation proposal for a first iteration in Document feature flag implementation proposal (!2759 - merged).

Proposal is merged and available here.