Add opensearch declaration (#1058)

* feat: Add opensearch declaration

* cleanup

---------

Co-authored-by: Johannes Zorn <johannes.zorn@zollsoft.com>
Co-authored-by: Sascha Ißbrücker <sascha.issbruecker@gmail.com>

bookmarks/urls.py

@@ -80,6 +80,8 @@ urlpatterns = [
     path("manifest.json", views.manifest, name="manifest"),
     # Custom CSS
     path("custom_css", views.custom_css, name="custom_css"),
+    # OpenSearch
+    path("opensearch.xml", views.opensearch, name="opensearch"),
 ]
 
 # Put all linkding URLs into a linkding namespace