Rationalize all db command output text

Right now it all feels a bit noisy as well as inconsistent. Maybe pare it back a little and keep it simple. Perhaps avoid using the `measure` block for most of these, since the timing doesn't feel that important, and `measure`'s handling of failures results in confusing back-to-front text ordering (i.e. the specific error messages first, and then the summary of the command that failed _underneath_ it).