Upgrade site and modules to Django 2.2. Remove and replace obsolete
functionality with current equivalents. Update requirements to latest
versions where possible. Remove unused dependencies.
Add flag to enable/disable raffle display on dashboard.
Add link from raffle winner to attendee profile.
Add URL for single raffle and base raffle path.
Show applied vouchers on attendee registration admin page.
Add head title and page title to more areas.
Update the dashboard to show warning for empty categories and have
button to open voucher page.
Fix exception on attendee page when user does not have attendee object.
Add shirt types and sizes. Improve messaging about discounts.
Restyle ticket wizard and product category screens. Enable page titles
and messages. Update dashboard to hide raffle.
Enable inventory population for dev container.
