Fix #978 -- Allow to split names (#1049)

- [x] attendee names
- [x] Invoice address names
- [x] Data migration
- [x] API serializers
  - [x] orderposition
  - [x] cartposition
  - [x] invoiceaddress
  - [x] checkinlistposition
- [x] position API search
- [x] invoice API search
- [x] business/individual required toggle
- [x] Split columns in CSV exports
- [x] ticket editor
- [x] shredder
- [x] ticket/invoice sample data
- [x] order search
- [x] Handle changed naming scheme
- [x] tests
- [x] make use in:
  - [x] Boabee
  - [x] Certificate download order
  - [x] Badge download order
  - [x] Ticket download order
- [x] Document new MySQL requirement
- [x] Plugins

src/pretix/base/views/mixins.py

@@ -80,8 +80,8 @@ class BaseQuestionsViewMixin:
                 # This form was correctly filled, so we store the data as
                 # answers to the questions / in the CartPosition object
                 for k, v in form.cleaned_data.items():
-                    if k == 'attendee_name':
-                        form.pos.attendee_name = v if v != '' else None
+                    if k == 'attendee_name_parts':
+                        form.pos.attendee_name_parts = v if v else None
                         form.pos.save()
                     elif k == 'attendee_email':
                         form.pos.attendee_email = v if v != '' else None