✨(backend) add creator field on document and allow filtering on it

We want to be able to limit the documents displayed on a logged-in user's
list view by the documents they created or by the documents that other
users created.

This is different from having the "owner" role on a document because this
can be acquired and even lost. What we want here is to be able to
identify documents by the user who created them so we add a new field.

src/backend/pyproject.toml

@@ -31,6 +31,7 @@ dependencies = [
     "django-configurations==2.5.1",
     "django-cors-headers==4.5.0",
     "django-countries==7.6.1",
+    "django-filter==24.3",
     "django-parler==2.3",
     "redis==5.1.1",
     "django-redis==5.4.0",