General improvements

If the following were addressed then this would be useful and improve consecutive registration:
- currently you can't modify the form/re-enter the form and add more guests attached to the main attendee
- currently you can't delete from attendees a guest if they are no longer attending
- refunding or making partial repayments changes the payment status back to partial or awaiting payment which means confirmation emails can't be sent only the failed payment email
- an easy option for all guest tickets to go to the main attendee
- the ability for a single confirmation of the main attendee to contain the qr codes for themselves and all their guests