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/session.config.ts

@@ -0,0 +1,18 @@
+import { SessionOptions } from "iron-session";
+
+export interface SessionData {
+	accessToken?: string;
+	refreshToken?: string;
+	userId?: string;
+}
+
+export const getSessionOptions = (password: string): SessionOptions => ({
+	password,
+	cookieName: "memegoat_session",
+	cookieOptions: {
+		secure: process.env.NODE_ENV === "production",
+		httpOnly: true,
+		sameSite: "strict",
+		maxAge: 60 * 60 * 24 * 7, // 7 days
+	},
+});