7653 Changes to auth interfaces
7653 CQL grammar changes and new statement classes
7653 Add roles to AuthenticatedUser
7653 Move legacy username/password constants to PasswordAuthenticator
7653 Move responsibility for role management to IRoleManager
7653 New configuration options
7653 Remove reference to username from PermissionsDetails
7653 Inherit superuser status from granted roles
7653 Restrict login to roles with that privilege specifically
7653 Migrate legacy auth data on upgrade
7653 Drop public Role class, only reference role names in auth ifaces
7653 Couple of fixes to validation & privilege checks on role statements
7653 Update cqlsh with roles

Also undo inconsistent quoting I introduced in #8370
7653 Clean up response messages
7653 Make column names consistent in internal auth tables
7653 Move auth keyspace definitions to separate class
7653 Break out user permissions cache into a separate class