- GitLab deployments using more than one application node should
  configure fast-keys authorization unless they are on CentOS 6.
- Database Migrations should be run post installation
- Clarify in the 2k, 3k, and 5k reference architectures that the
  `/etc/gitlab/gitlab-secrets.json` file must be the same for all
  application and gitaly nodes

Related https://gitlab.com/gitlab-org/gitlab-orchestrator/-/issues/193Signed-off-by: Robert Marshall <rmarshall@gitlab.com>