Core/RBAC: Simplify RBAC implementation

- Drop groups (roles than can have inherited roles) and roles (set of
  permissions)
- Permissions can now have inherited permissions (those act as roles)

RBAC DB structure is now limited to four tables
- rbac_permissions: Contains permissions and roles
- rbac_linked_permissions: Contains the relation between permissions and
  linked permissions (those permissions that have linked permissions are
  called roles)
- rbac_default_permissions: Contains the list of permissions to be granted
  to each security level [Added to maintain compatibility in an easy way]
- rbac_account_permissions: Contains the list of permissions granted or
  denied for a particular account.

NOTE: IF YOU ARE USING CUSTOM PERMISSIONS, ROLES OR GROUPS CHECK THE SQL
BEFORE APPLYING...

src/server/shared/Database/Implementation/LoginDatabase.cpp

@@ -98,14 +98,6 @@ void LoginDatabaseConnection::DoPrepareStatements()
 
     PrepareStatement(LOGIN_SEL_ACCOUNT_ACCESS_BY_ID, "SELECT gmlevel, RealmID FROM account_access WHERE id = ? and (RealmID = ? OR RealmID = -1) ORDER BY gmlevel desc", CONNECTION_SYNCH);
 
-    PrepareStatement(LOGIN_SEL_RBAC_ACCOUNT_GROUPS, "SELECT groupId FROM rbac_account_groups WHERE accountId = ? AND (realmId = ? OR realmId = -1) GROUP BY groupId", CONNECTION_SYNCH);
-    PrepareStatement(LOGIN_INS_RBAC_ACCOUNT_GROUP, "INSERT INTO rbac_account_groups (accountId, groupId, realmId) VALUES (?, ?, ?)", CONNECTION_ASYNC);
-    PrepareStatement(LOGIN_DEL_RBAC_ACCOUNT_GROUP, "DELETE FROM rbac_account_groups WHERE accountId = ? AND groupId = ? AND (realmId = ? OR realmId = -1)", CONNECTION_ASYNC);
-
-    PrepareStatement(LOGIN_SEL_RBAC_ACCOUNT_ROLES, "SELECT roleId, granted FROM rbac_account_roles WHERE accountId = ? AND (realmId = ? OR realmId = -1) ORDER BY roleId, realmId", CONNECTION_SYNCH);
-    PrepareStatement(LOGIN_INS_RBAC_ACCOUNT_ROLE, "INSERT INTO rbac_account_roles (accountId, roleId, granted, realmId) VALUES (?, ?, ?, ?) ON DUPLICATE KEY UPDATE granted = VALUES(granted)", CONNECTION_ASYNC);
-    PrepareStatement(LOGIN_DEL_RBAC_ACCOUNT_ROLE, "DELETE FROM rbac_account_roles WHERE accountId = ? AND roleId = ? AND (realmId = ? OR realmId = -1)", CONNECTION_ASYNC);
-
     PrepareStatement(LOGIN_SEL_RBAC_ACCOUNT_PERMISSIONS, "SELECT permissionId, granted FROM rbac_account_permissions WHERE accountId = ? AND (realmId = ? OR realmId = -1) ORDER BY permissionId, realmId", CONNECTION_SYNCH);
     PrepareStatement(LOGIN_INS_RBAC_ACCOUNT_PERMISSION, "INSERT INTO rbac_account_permissions (accountId, permissionId, granted, realmId) VALUES (?, ?, ?, ?) ON DUPLICATE KEY UPDATE granted = VALUES(granted)", CONNECTION_ASYNC);
     PrepareStatement(LOGIN_DEL_RBAC_ACCOUNT_PERMISSION, "DELETE FROM rbac_account_permissions WHERE accountId = ? AND permissionId = ? AND (realmId = ? OR realmId = -1)", CONNECTION_ASYNC);