feat: add two factor auth (#643)

Add two factor authentication for users who wish to enhance the security of their accounts.

packages/lib/server-only/2fa/verify-backup-code.ts

@@ -0,0 +1,18 @@
+import { User } from '@documenso/prisma/client';
+
+import { getBackupCodes } from './get-backup-code';
+
+type VerifyBackupCodeParams = {
+  user: User;
+  backupCode: string;
+};
+
+export const verifyBackupCode = async ({ user, backupCode }: VerifyBackupCodeParams) => {
+  const userBackupCodes = await getBackupCodes({ user });
+
+  if (!userBackupCodes) {
+    throw new Error('User has no backup codes');
+  }
+
+  return userBackupCodes.includes(backupCode);
+};