Updating test type URLs.

This pull request changes the URL for test types from ``/[campaignId]/[testType]`` to ``/[campaignId]/__attester__/[testType]`` so that everything inside ``/[campaignId]/`` is configurable in the campaign (through the ``resources`` parameter) without any risk of collisions with test type names (as it was before 5c6e86606fa306f22652bc1a3f711191defdbe5a).