feat: implement AuthModule with authentication and RBAC features

Added AuthModule with services, controllers, and guards for authentication. Implements session management, role-based access control, 2FA, and DTOs for user login, registration, and token refresh.

backend/src/auth/auth.module.ts

@@ -0,0 +1,16 @@
+import { Module } from "@nestjs/common";
+import { CryptoModule } from "../crypto/crypto.module";
+import { DatabaseModule } from "../database/database.module";
+import { SessionsModule } from "../sessions/sessions.module";
+import { UsersModule } from "../users/users.module";
+import { AuthController } from "./auth.controller";
+import { AuthService } from "./auth.service";
+import { RbacService } from "./rbac.service";
+
+@Module({
+	imports: [UsersModule, CryptoModule, SessionsModule, DatabaseModule],
+	controllers: [AuthController],
+	providers: [AuthService, RbacService],
+	exports: [AuthService, RbacService],
+})
+export class AuthModule {}