The snippets macro does not work anymore. It errors with "undefined method: render".

I believe it hasn't worked before as it tried to render a snippet from `app/views/unattended/snippets`, but the folder does not exist.

If I revert the template scope refactoring and create the folder, it errors with "AbstractController::DoubleRenderError in ProvisioningTemplatesController#preview"

In addition, the method is potentially dangerous as it allows a user to use ../

<%= snippets('../provisioning_templates/snippet/puppet.conf') %>

I was not able to break out of app/views but I guess we should not rely on that.