Cache column_exists? for application settings
This is most a backport of https://gitlab.com/gitlab-org/gitlab-ee/merge_requests/4987/diffs but includes other columns that use column_exists? in a way that may cause unnecessary schema loads.
This is most a backport of https://gitlab.com/gitlab-org/gitlab-ee/merge_requests/4987/diffs but includes other columns that use column_exists? in a way that may cause unnecessary schema loads.