Fix #277 -- Embeddable shop (#622)

* Vendor vue.js

* Refactor item_group_by_category to support vouchers

* Widget: Show product list

* Widget: free prices

* Widget: pictures and loading indicator

* Widget: First iframe steps

* Widget: Do not rerender iframe

* Widget: Error handling

* Improve widget

* Widget: localization tech

* Fix invoice style

* Voucher attribute and waiting list

* Add some iframe chrome

* First step to namespaced carts

* More isolation steps

* More cart isolation things

* More cart isolation things

* Mobile stuff

* Show cart on checkout pages

* PayPal and Stripe support

* Enable downloads

* Locale handling

* change text "save URL to this exact page"

* Widget: voucher redemption

* Widget: CSS

* CSS: Responsive

* Widget: CSS improvements

* Widget: Add embedding code generator

* Widget: Error messages and SSL check

* First tests

* Widget: tests

* Don't use IDs in widgets

* Widget: static files caching

src/tests/control/test_permissions.py

@@ -41,6 +41,7 @@ event_urls = [
     "settings/invoice",
     "settings/invoice/preview",
     "settings/display",
+    "settings/widget",
     "settings/tax/",
     "settings/tax/add",
     "settings/tax/1/",
@@ -167,6 +168,7 @@ event_permission_urls = [
     ("can_change_event_settings", "settings/email", 200),
     ("can_change_event_settings", "settings/display", 200),
     ("can_change_event_settings", "settings/invoice", 200),
+    ("can_change_event_settings", "settings/widget", 200),
     ("can_change_event_settings", "settings/invoice/preview", 200),
     ("can_change_event_settings", "settings/tax/", 200),
     ("can_change_event_settings", "settings/tax/1/", 404),