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

doc/api/resources/checkinlists.rst

@@ -371,6 +371,9 @@ Order position endpoints
             "variation": null,
             "price": "23.00",
             "attendee_name": "Peter",
+            "attendee_name_parts": {
+              "full_name": "Peter",
+            },
             "attendee_email": null,
             "voucher": null,
             "tax_rate": "0.00",
@@ -466,6 +469,9 @@ Order position endpoints
         "variation": null,
         "price": "23.00",
         "attendee_name": "Peter",
+        "attendee_name_parts": {
+          "full_name": "Peter",
+        },
         "attendee_email": null,
         "voucher": null,
         "tax_rate": "0.00",