Warning about un-replicated data in DR failover
This issue is intended to separate the easy part (add basic warnings) that we can do immediately, from the hard part in https://gitlab.com/gitlab-org/gitlab-ee/issues/4210.
When a disaster occurs and a secondary is promoted, there may be data that successfully saved to the primary but was not replicated to the secondary before the disaster occurred. This data should be treated as lost.
The administrator should be warned of this in the docs and in the promote to primary script.
/cc @jramsay