Improve Perma Roles

[Defelo]

Make the member parameter of .roles perma_add and .roles perma_unset optional. If this parameter is omitted, create perma role entries for all users who have this role and add this role to a new table to mark it as permanent. Adding a permanent role to a member will also add a new db entry for this user and removing the role will also remove the db entry without reassigning the role. When a user leaves and rejoins the server, reassign all perma roles of this user.