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/app.module.ts

@@ -5,6 +5,7 @@ import { AppService } from './app.service';
 import loadEnv from './config/env';
 import { DatabaseModule } from './database/database.module';
 import { AuthModule } from './modules/auth/auth.module';
+import { PrivilegesModule } from './modules/privileges/privileges.module';
 import { UsersModule } from './modules/users/users.module';
 
 @Module({
@@ -16,6 +17,7 @@ import { UsersModule } from './modules/users/users.module';
     DatabaseModule,
     UsersModule,
     AuthModule,
+    PrivilegesModule,
   ],
   controllers: [AppController],
   providers: [AppService],