DB/Core: The Storm King's Vengeance
Core/RBAC: Move RBAC code to namespace rbac
Core/RBAC: Add default groups to accounts based on their security level.
- Removed config option RBAC.DefaultGroups

Use the table rbac_security_level_groups to configure the groups to be added to the account at load time.

Note: Those groups are only used at run time, never saved to DB