Implement privilege middleware across the controllers

[malexandert]

We already require Users are logged in to do basically anything in the API. We should also require that the logged in User has an appropriate auth level, as defined here

• 'None' Auth

  1. Shouldn't be able to do anything. These are pending users that must be approved by an Admin before they can use their account

• 'User' Auth

  1. Should be able to search for and view basically everything: Users, artists, albums, programs, playlists, etc.
  2. Should be able to edit their own User information and create/edit/delete playlists on their own shows/in random playlists

• 'Exec' Auth

  1. Should be able to promote users to Exec level from User level, and demote users from Exec level to User level
  2. Should be able to create, update, and delete programs, artists, albums
  3. Should be able to approve pending users

• 'Admin' Auth

  1. Should be able to promote/demote users to any auth level