Organizer-level plugins (#5305)

* Add version notes to the docs

* Adapt signal handling

* Add UI

* Add API

* API and tests

* Fix registry

* Update doc/development/api/plugins.rst

Co-authored-by: Felix Rindt <felix@rindt.me>

* Fix failing tests

* Apply suggestions from code review

Co-authored-by: Richard Schreiber <schreiber@rami.io>

* Update src/pretix/control/templates/pretixcontrol/organizers/plugin_events.html

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

* Update src/pretix/control/templates/pretixcontrol/organizers/plugins.html

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

* Update src/pretix/control/templates/pretixcontrol/organizers/plugins.html

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

* Update src/pretix/control/navigation.py

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

* Update src/pretix/control/urls.py

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

* Apply suggestion from @wiffbi

* REbase migration

* Fix review note

* Fix test cases

* Remove plugin from all events if disabled on org level

* Update doc/development/api/plugins.rst

* Unify registries

* Rebase migration

---------

Co-authored-by: Felix Rindt <felix@rindt.me>
Co-authored-by: Richard Schreiber <schreiber@rami.io>
Co-authored-by: luelista <weller@rami.io>

src/pretix/control/navigation.py

@@ -495,6 +495,13 @@ def get_organizer_navigation(request):
                     }),
                     'active': url.url_name == 'organizer.edit',
                 },
+                {
+                    'label': _('Plugins'),
+                    'url': reverse('control:organizer.settings.plugins', kwargs={
+                        'organizer': request.organizer.slug,
+                    }),
+                    'active': url.url_name == 'organizer.settings.plugins' or url.url_name == 'organizer.settings.plugin-events',
+                },
                 {
                     'label': _('Event metadata'),
                     'url': reverse('control:organizer.properties', kwargs={