Mega-issue: Registration Email Changes

[dunkOnIT]

This is a combination of a number of different issues: #7388, #6822, #5328, #3121

• Overall: Once the below issues are handled, there should be a general review of the emails we send - ensuring that all status changes are covered.

High

• Change Pending Email away from the "Waiting List" email (currently the user is sent the "Waiting List" email when they get moved to competing_status: pending - but only when moved back to pending, not when they initially sign up)
• When the user re-registers after cancelling, just send the same "You've registered!" email that we did the first time - currently we send them the bad "Waiting List" email

Medium:

• Consider adding a delay (~2-5min?) when sending status change updates to competitors, in case the organizer has to move them around a bit/makes a mistake the first time they move them (this should make it so that only the user's final status is emailed, instead of receiving one email for every status change)
• Waiting List email: Currently we don't send any email when the user is placed on the waiting list. The email should: Tell the user they're on the waiting list, what this means, and their current numbered position on the waiting list [Improve the automatically generated email when placed on the waiting list #6822]
• Email the user telling them their registration is cancelled when they cancel their registration - currently we don't send any notification of this to the user
• Allow organizers to specify a cancellation reason when cancelling/rejecting a registration, which gets sent to the user in the status change email [Allow organizers to specify a reason which gets included in the Cancellation email when cancelling/rejecting a registration #5328]
• Notify organizers of edits to a user's registration
• Include the comment of a registration in the notification email when a user cancels their registration [Improve notifications from competitions for organisers of that competition #7388]

Low:

• Give organizers greater control over email notifications: Allow them to either choose a batched email, turn emails on/off, or only sign up for certain notifications (first implement auto-accept, as this removes a lot of the need for organizers to receive emails saying that a user has signed up) [Better email notification system #3121, Improve notifications from competitions for organisers of that competition #7388]