* feat: Member roles are implied and never exlpicitly added
* Rename "GetAllUserRoles" to "GetAuthorizationRoles"
* feat: Add migration to remove implied roles
* rename user auth role middleware
Abstracting coderd into an interface added misdirection because
the interface was never intended to be fulfilled outside of a single
implementation.
This lifts the abstraction, and attaches all handlers to a root struct
named `*coderd.API`.