feat(backend): Add instance id for linked data plugins (#9087)

* feat(backend): Add instance id for linked data plugins

* add to settings ui

* fix ref name

* add test

* fix default

* remove wrong key

* fix serializer

* fix patching

src/frontend/src/pages/Index/Settings/SystemSettings.tsx

@@ -42,6 +42,8 @@ export default function SystemSettings() {
             keys={[
               'INVENTREE_BASE_URL',
               'INVENTREE_COMPANY_NAME',
+              'INVENTREE_INSTANCE_ID',
+              'INVENTREE_ANNOUNCE_ID',
               'INVENTREE_INSTANCE',
               'INVENTREE_INSTANCE_TITLE',
               'INVENTREE_RESTRICT_ABOUT',