This is helpful for applications like the dashboard that use static
typing and can use the `AnyPermission` type to catch typos and
missing/renamed permission names during the build phase.

This endpoint removes the need setting media eintries through the media
endpoint. This is helpful because a lot of operations that clients will
usually do, like adding new, deleting old, or reordering media sources
becomes non-atomic when operating on lists.

This mixin factory makes it easy to create atomic reorder operations for
entities that have a static numeric order criteria that is supposed to
be updated by clients.