Switch to 'secret variable' name in variables endpoint API docs
Both web UI as well as other docs use 'secret variable' name instead of currently used 'build variable' in the API docs. This MR is to unify this by changing the API docs.
Do not update/delete: Banner broadcast message test data
Do not update/delete: Notification broadcast message test data
Both web UI as well as other docs use 'secret variable' name instead of currently used 'build variable' in the API docs. This MR is to unify this by changing the API docs.