Add privilege management system with related migrations and guards

- Introduced a new `PrivilegesModule` to manage user privileges and access control.
- Added `RequirePrivilege` decorator to enforce privilege checks on controller handlers.
- Implemented `PrivilegesGuard` to handle authorization based on user privileges.
- Created database migrations for `privileges`, `privilege_keys`, and `privilege_details` tables.
- Updated user model to include `is_superadmin` field for enhanced access control.
- Added unit tests for the new privileges functionality and guards to ensure correct behavior.

src/modules/auth/strategies/jwt.strategy.ts

@@ -45,6 +45,7 @@ export class JwtStrategy extends PassportStrategy(Strategy, 'jwt') {
       id: user.id,
       username: user.username,
       jti: payload.jti,
+      isSuperadmin: user.isSuperadmin,
     };
   }
 }