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/common/auth/auth-user.ts

@@ -2,6 +2,7 @@ export type AuthUser = {
   readonly id: string;
   readonly username: string;
   readonly jti: string;
+  readonly isSuperadmin: boolean;
 };
 
 export type JwtAccessPayload = {