Automated role management: create hoisted roles

Users would like to be able to choose a specific top-most affiliation alongside all of their other roles. We can achieve this in Discord by creating a duplicate role for each hoisted role, and then allowing users to choose hoisted versions of them.

e.g. `!role make-hoistable C` would make a "C (hoisted)" role of the same color as the "C" role, and add it to the list of roles a user can pick.