Consider adding ArrivalTime and DepartureTime to Student Attendance entities

This suggestion is based on a review of current state implementation extensions and from feedback from a recent SIS survey on how attendance duration is captured.

While EventDuration allows for this information to be captured, the decimal datatype can be cumbersome for some systems.

DATASTD-1307 proposes adding Duration elements to all Student Attendance entities.

When the SIS's were surveyed, all respondents indicated they collect ArrivalTime and DepartureTime along with other options. Adding these elements as optional to all Student Attendance entities could eliminate some unnecessary business logic in the data mappings and provides another avenue to record the attendance duration.