Add Expiration Date to Products

[bobort]

To allow subscription-based products, add an expiration date field to the staff report. Group it by date.

For Ocean Courage, the initial date must be June 1, 2019, even if it was purchased before then. Ocean Courage is a 1-month subscription, so add 1 multiplied by the total quantity purchased to the month of the initial date. Staff must be able to adjust expiration dates as necessary.

[bobort]

Send emails to proper personnel when a subscription expires. Possibly copy some data from Zoom API to be more fair.