DRILL-4782 / DRILL-7139: Fix DATE_ADD and TO_TIME functions
- cast function for the day interval changed to round milliseconds to complete days
- ToDateTypeFunctions#toTime now returning milliseconds of day
- updated the way how DayInterval subtracts and adds, to follow the cast function logic
UT core updates:
- added vectorValue function to the queryBuilder to simplify retrieving value of the vector
- refactored singleton query result functions at queryBuilder
