Formats time in seconds according to a format.
Intended to show time elapsed, rather than time-of-day.
|_seconds||Number of seconds to format, for example from ‘time’ command [number]|
|_format||Format to put time into [String: “H:MM:SS”, “M:SS”, “H:MM:SS.mmm” or “M:SS.mmm”; defaults to “H:MM:SS”]|
Formatted time [String]