Allow injection of a validator for numeric values of
the date-time fields, to allow for these to be displayed
as invalid in cases where the text itself may be parsed
but the resulting value is not valid (e.g. when start
is greater than end.)
https://github.com/nasa/openmctweb/issues/325
...on watches triggered from the picker. Only want to
trigger a submit when this actually constitutes a change from
the datetime field's underlying model (to avoid triggering
form submission when datetime picker is initialized.)
Use default format when no format is specified, and throw an
error when a specified format is unrecognized, from both
date-time field controller and time range controller.
