Pluggable permissions (#5728)

* Data model draft

* Refactor query and assignment usages of old permissions

* Backend UI

* API serializer

* Big string replace

* Docs, tests and fixes for teams api

* Update docs for device auth

* Eliminate old names

* Make tests pass

* Use new permissions, remove inconsistencies

* Add test for translations

* Show plugin permissions

* Add permission for seating plans

* Fix plugin activation

* Fix failing test

* Refactor to permission groups

* Update doc/api/resources/devices.rst

Co-authored-by: luelista <weller@rami.io>

* Update doc/api/resources/events.rst

Co-authored-by: luelista <weller@rami.io>

* Update src/pretix/api/serializers/organizer.py

Co-authored-by: luelista <weller@rami.io>

* Fix typo

* Fix python version compat

* Replacement after rebase

* Add proper permission handling for exports

* Docs for exporters

* Runtime linting of permission names

* Fix typos

* Show export page even without orders permission

* More legacy compat

* Do not strongly validate before plugins are loaded

* Rebase migration

* Add permission for outgoing mails

* Review notes

* Update doc/api/resources/teams.rst

Co-authored-by: Richard Schreiber <schreiber@pretix.eu>

* Clean up logic around exporters

* Review and failures

* Fix migration leading to forbidden combination

* Handle permissions on event copying

* Remove print-statements

* Make test clearer

* Review feedback

* Add AnyPermissionOf

* migration safety

---------

Co-authored-by: luelista <weller@rami.io>
Co-authored-by: Richard Schreiber <schreiber@pretix.eu>

src/pretix/api/serializers/settings.py

@@ -37,6 +37,8 @@ logger = logging.getLogger(__name__)
 class SettingsSerializer(serializers.Serializer):
     default_fields = []
     readonly_fields = []
+    default_write_permission = 'organizer.settings.general:write'
+    write_permission_required = {}
 
     def __init__(self, *args, **kwargs):
         self.changed_data = []
@@ -58,9 +60,17 @@ class SettingsSerializer(serializers.Serializer):
             f._label = str(form_kwargs.get('label', fname))
             f._help_text = str(form_kwargs.get('help_text'))
             f.parent = self
+
+            self.write_permission_required[fname] = DEFAULTS[fname].get('write_permission', self.default_write_permission)
+
             self.fields[fname] = f
 
     def validate(self, attrs):
+        for k in attrs.keys():
+            p = self.write_permission_required.get(k, self.default_write_permission)
+            if p not in self.context["permissions"]:
+                raise ValidationError({k: f"Setting this field requires permission {p}"})
+
         return {k: v for k, v in attrs.items() if k not in self.readonly_fields}
 
     def update(self, instance: HierarkeyProxy, validated_data):