Replace disable FFs by disallow_database_ddl_feature_flags
What
Change steps to enable/disable/get feature flags to single FF disallow_database_ddl_feature_flags
- gitlab-org/gitlab!130554 (merged)
Reference TODO: https://gitlab.com/gitlab-com/gl-infra/reliability/-/issues/24342#note_1540196702
Test issue is #22
Why
Makes life simpler and happier during postgresql maintenances
I implemented all @alexives recommendations at !486 (merged) regarding disallow_database_ddl_feature_flags
in this MR so it would be easier to review and revert
Edited by Rafael Henchen