authz: refactor providers init logic to their own packages
Created by: unknwon
This PR is a prerequisite for merging https://github.com/sourcegraph/sourcegraph/pull/6427 because it fixes the cyclic import compile error.
Test plan: CI
Created by: unknwon
This PR is a prerequisite for merging https://github.com/sourcegraph/sourcegraph/pull/6427 because it fixes the cyclic import compile error.
Test plan: CI