Add support for reserved seating (#1228)

* Initial work on seating

* Add seat guids

* Add product_list_top

* CartAdd: Ignore item when a seat is passed

* Cart display

* product_list_top → render_seating_plan

* Render seating plan in voucher redemption

* Fix failing tests

* Add tests for extending cart positions with seats

* Add subevent_forms to docs

* Update schema, migrations

* Dealing with expired orders

* steps to order change

* Change order positions

* Allow to add seats

* tests for ocm

* Fix things after rebase

* Seating plans API

* Add more tests for cart behaviour

* Widget support

* Adjust widget tests

* Re-enable CSP

* Update schema

* Api: position.seat

* Add guid to word list

* API: (sub)event.seating_plan

* Vali fixes

* Fix api

* Fix reference in test

* Fix test for real

src/tests/presale/test_widget.py

@@ -133,6 +133,7 @@ class WidgetCartTest(CartTestMixin, TestCase):
             "vouchers_exist": False,
             "waiting_list_enabled": False,
             "error": None,
+            "has_seating_plan": False,
             "items_by_category": [
                 {
                     "items": [
@@ -214,6 +215,7 @@ class WidgetCartTest(CartTestMixin, TestCase):
             "currency": "EUR",
             "show_variations_expanded": False,
             "display_net_prices": False,
+            "has_seating_plan": False,
             "vouchers_exist": True,
             "waiting_list_enabled": False,
             "error": None,
@@ -262,6 +264,7 @@ class WidgetCartTest(CartTestMixin, TestCase):
             "show_variations_expanded": False,
             "display_net_prices": False,
             "vouchers_exist": True,
+            "has_seating_plan": False,
             "waiting_list_enabled": False,
             "error": None,
             "items_by_category": [
@@ -324,6 +327,7 @@ class WidgetCartTest(CartTestMixin, TestCase):
             "currency": "EUR",
             "show_variations_expanded": False,
             "display_net_prices": False,
+            "has_seating_plan": False,
             "vouchers_exist": True,
             "waiting_list_enabled": False,
             "error": "This voucher is expired.",