Discount Code improvements for GoToTraining

[Julian Byrne]

1. It would be great to have an option to enter a date range or at least expiry date for discount codes associated with GoToTraining sessions.

Examples of uses include:
Early Bird Discounts, Flash Sales, Last Remaining Seats, 1 time promotions (ie: Free)

2. It would be great to have the option to specify the amount of times a discount code can be used (ie: 10 times or $1000 worth)

[JourneyHS]

These are good ideas.  It would also be good to allow for these codes to be entered once and tied to any training.  As it stands now you have to setup codes by training and that means duplicate work.