Trunk-4444 Validate order overlap with scheduled date

Trunk-4444 Implementing feedback on earlier commit

Trunk-4444 Adding void order check while checking overlapping schedule of orders

Trunk-4444 Moving checkoverlap method to OrderUtil

Follow up to ensure that orders that start or end on dates equal to other orders' start and end are considered to be overlapping  - TRUNK-4444

Follow up to ensure that orders that start or end on dates equal to other orders' start and end are considered to be overlapping  - TRUNK-4444