Add post and image deletion

This one was kind of a doozy. This also adds a custom 403 error page and
fixes some permission denied behavior that I was having issues with for
a while.

This is also set up in a way that hopefully will allow me to easily
implement user post deletion.

Signed-off-by: Alek Ratzloff <alekratz@gmail.com>

board/urls.py

@@ -19,12 +19,18 @@ urlpatterns = [
     # Bans
     path("ban/<slug:url>/<int:id>/", BanCreateView.as_view(), name="ban_create"),
     path("ban/success/", BanSuccessView.as_view(), name="ban_success"),
-    path("banned", BannedView.as_view(), name="banned"),
+    path("banned/", BannedView.as_view(), name="banned"),
     # Other moderation pages
     path("modify/<int:pk>/", PostModifyView.as_view(), name="post_modify"),
     path(
         "modify/success/", PostModifySuccessView.as_view(), name="post_modify_success"
     ),
+    path("post/delete/<int:pk>/", PostDeleteView.as_view(), name="post_delete"),
+    path(
+        "post/delete/success/",
+        PostDeleteSuccessView.as_view(),
+        name="post_delete_success",
+    ),
 ]
 # TODO - make this conditional so we can serve images up with whatever server we want
 urlpatterns += static(settings.MEDIA_URL, document_root=settings.MEDIA_ROOT)