Allow extended unit names for days, hours, minutes, seconds, milliseconds in expire duration parser

[jimtng]

Please merge #4868 first.

Extend the expire/duration parser syntax to allow optional spaces between the number and its unit and accept alternative units:

• d|day|days
• h|hr|hrs|hour|hours
• m|min|mins|minute|minutes
• s|sec|secs|second|seconds
• ms|millisecond|milliseconds