Deal with unused stubs for custom permissions providers

[mrcnski]

ISSUE

Overview

Either:

1. remove the stubs for custom permissions providers (getPermissionsProviderUrl), or
2. fully implement them if we actually still want to have custom permissions providers. This is from when we decided that users can choose their own permissions providers, but we didn't yet have a way to access/save user settings.

I'm not sure if this question is even relevant still with the upcoming kernal changes.