Hide the Advanced Credit catalog from learners

We need a toggle to block specific users, ideally learners, from seeing our full Advanced Credit catalog. The full list creates unhelpful and unnecessary competition given how we run crediting.

Admins and faculty should still see the full catalog. Learners should only see what we choose to show them.

Requested by Mindy Roth, Mastery School of Hawken.

Source: https://feedback.mastery.org/p/mastery-school-of-hawken-initial-wishlist