Performance: replace django-treenode with adjacency-list tags (#14612)

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Co-authored-by: Codex <267193182+codex@users.noreply.github.com>

src/documents/admin.py

@@ -1,7 +1,6 @@
 from django.conf import settings
 from django.contrib import admin
 from guardian.admin import GuardedModelAdmin
-from treenode.admin import TreeNodeModelAdmin
 
 from documents.models import Correspondent
 from documents.models import CustomField
@@ -29,7 +28,7 @@ class CorrespondentAdmin(GuardedModelAdmin):
     list_editable = ("match", "matching_algorithm")
 
 
-class TagAdmin(GuardedModelAdmin, TreeNodeModelAdmin):
+class TagAdmin(GuardedModelAdmin):
     list_display = ("name", "color", "match", "matching_algorithm")
     list_filter = ("matching_algorithm",)
     list_editable = ("color", "match", "matching_algorithm")